If you live with the person you are caring for do you pay rent All the bills? Do you get paid?

Who says talking finances is taboo? Your husband's family? I think you are being used. I think you know that.

Who is going to fund your retirement?

Why isn't your MIL on Medicaid? Does she collect Social Security?

Isn't your blind autistic BIL getting SSDI? Isn't he eligible for placement in a group home?

I think I'd start planning on moving out quite soon.

It sounds like the family is accusing you of free loading and is not appreciative of the care you've provided. If that's the case your best option may be to move out and support yourselves on your own. If that is not easily doable because you and/or your husband don't work or have limited opportunities or ability to then you're in a bit of a bind and may have to be agreeable to and put up with the family but if you and your husband can support yourselves on your own I would suggest you start to think about washing your hands of the situation and move out. Then the sisters in law will have to do more than visiting on Sundays for lunch and you would be more in control.

You never pay for anything.
You pay all the bills except the mortgage.
Your mother in law has outlived her funds.
"We" are down to near nothing

And what about BIL's income, he must have some sort of entitlement to support?

There are conflicting statements in your post; this isn't a criticism, it's just that to me it sounds as if there has just been a huge row/shouting match and perhaps no one was actually trying to get the numbers down on paper?

Because I think that would be a useful first step. You all of you need to come up with a plan. No good saying "keep emotions out of it" because it's ALL highly emotive; but the crucial thing is where to go next, and to make sense of that you need to see what you've got to work with.

And Dearest Husband is where in all this? Out at work? Hiding in his shed?

What is a 92 yr old doing with a Mortgage. I think what ur doing is OK. Everyone, even BIL, should be paying for their personal needs.

It maybe time to say that if they don't like the arrangement, they can take over Mom's and brothers care. You have done ur share.

I would, if Mom passes, no longer care for BIL. A place can be found for him, like a group home. Stress can cause all kinds of health problems. Time to take care of yourself.

An attorney can see that you get paid legally for the care but since you are in their home and not the other way around, they may ask you for rent. Need to get a lawyer to set things up legally or get them in a facility and apply for medicaid and sell the house. If no one has POA you need to get one. See a lawyer. Protect yourself.

Kim, how incredibly tragic, and I cannot imagine your doing this. You have such good advice below I hesitate to say a thing. I am with those who suggest that it may be time for this home to be sold and your MIL and BIL placed in care. Would your husband agree to this? Because otherwise you two on on for sacrificing your entire lives to this, and certainly the BIL likely to outlive you both.
As to payment. That is quite insane to my mind. I do agree with those who suggest you pay for one hour of elder law attorney type to run this past. The BIL must have some sort of funds, and that should be used with him the "subject". I am assuming you are the POA?
Now as to Sister in Law. Is this the first she is problematic? In all this time? If so I would ask her over. I would be grey rock here (google "going grey rock"). I would not be tricked into argument or explosions of anger. I would tell her you will begin speaking and will speak uninterrupted and then it will be her turn and you will listen. I would say exactly what you said above. What you have done. What you do do. Then I would say that you would love now to have a real life, and to pursue placement of your MIL and BIL so you can have some quality of life before you die. I would tell her that if you do stay the payment of mortgage and bills now will come out of the finances left in MIL and BIL, and that you will go to an attorney to accomplish this. I would suggest that if SIL is not happy with this that she seek guardianship. She can when she wins this take the MIL and BIL into her care, or place them; that you will be very happy to move on with your lives at that point. OR, she can request of the court that MIL and BIL become wards of the state and placed by the state.
To my mind, if you are doing all the care you should not be paying rental OR utilities and should in fact have any financial help your family can manage if there are any funds they can spare (that last was to give you a laugh at the end of this).
Now. The choices here really are this. Are you going to continue to sacrifice your own lives in the care of the two? And your health. Go to an early grave with one or both of them left behind?
Where does your husband fit in here in the care of his mother and brother? Is he also hands on or is he working most of the time.
I cannot imagine what you have taken on. I could not for a single second of my life do this. I am so sorry.

I am my 92 year old mom's live in caregiver, along with my husband and 2 sons. My 4 siblings are aware of our sacrifice of free time and privacy. We tell them when vacations are planned or we have an event so they can mom sit. The house is paid off so no mortgage, and mom asked me to pay for groceries as we were 4 people and she was used to feeding only herself. We have taken over many duties that she paid for, lawn etc. When we moved in with her at her request, she was still working. She developed dementia and gradually I became her caretaker. In the end , I will either buy out my siblings, or sell her house and move on. My goal is to help my mom remain at home as long as she can. It is hard, and we are a close family. You need to speak up if you need help. Take a vacation and make SIL stay and see what you do on a daily basis.

Talking about finances should not be taboo. Really.

I'll tell you what my ex-husband's arrangements are with his parents, and I'll say which I think are good and which I think aren't good.

1) Ex was being paid by his parents and might still be. Good. (He was doing work, for which he should be paid.)
2) Ex is being paid cash by his parents. Not good. (Ex probably was hiding some of the money before and during our divorce.)
3) Ex does not have a caregiver agreement. Not good. (Without an agreement, the money paid to him above a certain amount, whether in cash or not in cash, would be considered a divestment for Medicaid purposes.)
4) Ex does not pay rent or contribute to other household expenses. Good. (For Medicaid purposes, ex's payments might be considered gifts to his parents.)

If not for this in-home care, ex's parents would have to reside in long-term care facilities. The costs would be much higher for that than what they are paying my ex and the free room and board they are providing to him.

I have other concerns about the situation, but they have to do with other than the financial arrangements.

Call an elder-attorney. Your brother-in-law and mother-in-law could be able to go into professional assisted living under a Medicaid claim. The attorney should be able to direct you.

"We have had this overwhelming responsibility for 12.5 years! We at the time thought his mom was so sick she wouldn't live more than 2 yrs max. now yrs later here we are."

I just fell out of my chair. Wow! I had been caring for my parents for 12.5 years (my father died in December), and only moved in for a max of 2 years due to their health. Like many of the immortals (people who live to their 90s and 100s) they are out living their savings.

When the Princess (my younger sister and their favorite) told me I should be paying rent since I lived with them 24/7, I told her the live-in staff on Downton Abbey do not pay room and board.

She is worried she will not be inheriting a lot of money. I have already stopped the habit of the oldsters giving her a check whenever she came by. Even though she works less than ten minutes away, her visits are usually only once a month for 1-2 hours. She comes in unannounced, think a SWAT team no knock raid, to complain, guilt trip, or use the parents as emotional tampons. Yes, my mother still wants her to have a key so she feels welcome anytime.

I keep very details records where every dollar has gone. I cannot stress enough to have a good paper trail. Already told my sister that the savings are running out due to low interest rates and high medical expenses. I think my sister is going to be surprised to learn her half of the estate is very little. $2 divided by 2 is $1.

I also am dealing with my late father's rental property. Before anyone starts thinking that is a great income source, he liked to fix up cheap houses in mill towns that he bought at auction. Currently, I have one of the last ones for sell for $15K. Yes, there are livable houses that cheap in the South.

At 68, my health is declining from the stress of caring for a 94-year old nagging hag. Also, for entertainment and money, I have start the Swedish Death Cleanse at the house. My dead Dad's stuff, my Mothers stuff, and my stuff. My mother likes to tell me the history of the things she and Daddy acquired during their 70 years of marriage.

Keep trying to survive. The most critical relatives are the ones who will not help. Also, work on your exit plan. I will be escaping in 2 years. The assets will be liquid, and the current house will be completely ready to sell. My Mother will be put in a home when she needs that level of care.