Need advice with parents going blind & dementia & stubbornness.

Bless you (and your hubs) for being willing to make such a personal sacrifice. The problem with "family helps family" is no one ever realizes how intense and ugly it often gets. A daily grind and grind and grind. If anyone could know what it would actually be like, they'd NEVER agree to doing it. First, your sister was "assumed" into this role, and now you and your husband. How do you know that your mom doesn't also have the beginnings of cognitive decline? Loss of filter and nastiness can be a symptom. Who is DPoA for your parents? I wouldn't go a step further without them creating the legal structure for you and/or your sister to manage their care as it will eventually become a poop show without this ability. You and your sister are not obligated to care for your parents. And besides, there are 2 of them. Impossible without burning you out and wrecking your marriage. Your first obligation (and boundary) is to your husband. He certainly wouldn't have knowingly signed up for this duty. Perhaps you should consider seeing a therapist who will help you identify boundaries (because in a dysfunctional relationship they can be very murky). What you are experiencing is extremely common outcome when parents don't have realistic plans for their aging. Aging-in-place or "staying independent for as long as possible" is a romanticized notion that is only seen on tv or in the movies. Physical decline is one thing. Cognitive decline is a whole other ball game. Please read some of the posts from loving and well-meaning adult children who were assumed into caregiving reticent parents and are now on fire on their way to total burnout (and some who are still struggling to recuperate even after the passing of their parent). Ultimately the caregiving arrangement has to work for both the giver and receivers. It can't be onerous to either. In your case it surely is not working and will only get more intense. If I were in your shoes I'd maybe start with a scripted discussion with your mother (scripted so that it doesn't veer off into emotional and unproductive arguing). Then I'd definitely work on getting DPoA for them (or at least her) and plant your flag in this as a condition for you to continue providing and managing her care. Then I'd work on getting her an appointment for a cognitive exam (and this will be a discrete request by you to her doctor because it's doubtful your mom would do this voluntarily). I handed my MIL's doctor a note telling her who I was and why we were concerned for her and requesting they do a cognitive/memory exam and they were glad to do it). Once you have that *after* her creating a DPoA then moving forward with care plans will be legally easier. There is much to process and do in your situation. Eat the elephant one bite at a time (that's what I had to do in my situation). You will get much wisdom and useful info from this forum. Peace to you!

I guess your sister is very relieved that you showed up to take over the care of your parents. Now that you're seeing what it's like, I guess you can't blame her, right?? I mean, I would sure love someone to come take over too! LOL. But, I know, it is NOT funny, it is difficult, beyond words.

I can totally understand not wanting to visit your parents except on days that you are on duty. Caregiving is hard and your mom is not making it any easier.

You are going to figure out what you are and are not willing to do and set some clear boundaries with your mom. She will not like it. She will act up. Be ready for it and have a plan of action. There are books on this and if I were you I'd read some and make a plan ASAP to take back your sanity.

Your parents may not want outside help, but it is not their choice to decide how you should spend YOUR time. You get to choose.

Why can't you see your kids/grandkids for 2 years?? This is your family and there has to be a way to make it happen. You must miss them so much! I would be so incredibly sad without access to mine!

So get busy setting some boundaries and getting some outside help for them, whether they like it or not.

Well..this may be harsh but since mom is cognizant have you sat her down and told her what you have put in writing here?
Blind or not she needs to open her eyes and understand what you are dealing with.
Point blank tell her that you have to cut back the days you help her. Give her 2 days a week that you will be able to take her to appointments and help her out.
AND tell her that if she bullies you, snaps at you you are not going to listen to it if she will not take constructive suggestions. (If you are on the phone, hang up. If you are at a store say "we are leaving and leave everything where it is and go. If you are in her home, get up and leave.. you get the idea)
If she does not want to accept help from caregivers then she is on her own.
If caring for dad is difficult for her and she will not have help from hired caregivers the option is to place him in Memory Care.
I would also tell her that you are making plans to move back "home" and suggest that she be open to Assisted Living or at least accepting caregivers.