How much should I charge my mother-in-law to live with me? Is it OK?

I never had to charge my folks rent because they offered freely, They paid the extra cable, and the Costco bills and gas for the cars. So at that point it didn;t cost me much more.. except for the heating , as mom was always cold! She paid for alot of "extras" and I know we were lucky. But if they had not, then yes I would have come up with a plan for them to help

You should charge her rent.
I would divide the household expenses by the number of people.
So if it is you, your husband and MIL you would take ALL the household expenses and divide by 3. If there are 3 kids living at home then you would divide by 6. (frankly if you have 3 kids living at home and if they have jobs they should be kicking in $$ as well)
The fact that she paid to convert the garage if that significantly added value to your property I might reduce her portion of what she should be paying.

Take 30 % of her social security and charge some Money for utilities . Ask for $500 and some Money for weekly grocery shopping or let her get SNAP Benefits .

If your kids are still minors, don't factor in their cost of rent and living expenses as if they were adults. They are not adults and kids don't pay for rent, food, taxes, or utilities.

Your mother has her own place at your house. Not a bedroom like the kids have. An apartment. Her own apartment. So she can pay an actual rent and utilities for it.

You should not feel bad for one second charging her rent and utilities. That's common sense. You do her laundry, shopping. errands, and everything else and you have not mentioned even one time about compensation for all that, so I'm assuming you're doing it for free. That's very generous because hiring a homecare agency to do for her would cost her a fortune.

So yes, you should be charging her for rent and utilities costs.

Of course it's OK for her to reimburse you for her share of the living expenses. If she has income she needs to be using it for her needs. I feel this is especially true if there are siblings that will expect to share in her estate when she dies. You shouldn't be expected to cover her living expenses and then share equally at her death.

If you are the only heir and you can afford it, it probably doesn't matter much. But it sounds as if your living expenses are taking a hit with her living with you. Work out something fair, it will help the whole arrangement work better.

Of course, you can charge her for living expenses. It’s costing money. It’s only fair that you are reimbursed.

Regarding all the help that's going to be required, showering her a few times after surgery isn't quite the same as having to do it to keep her clean all the time. Dementia patients get slippery and slidey, and when they start objecting to being clean, they can be afraid of the water, the tub or even you. If I were you, I'd be looking into resources now so you'll have a plan later. When in the middle of the actual difficulty, you'll be glad you have somewhere to turn.

It would be a good idea for you to have a conversation with her about leaving some money - a larger amount, like a couple of thousand dollars - with you for incidental expenses. As her condition worsens (and dementia patients can go downhill really fast), you may need to spend your own money on her. Since she seems to have plenty, you shouldn't do that.

An example would be, when I was caring for my dad at his house, we had two caregivers, my mother and her friend, dad, and then me and another friend who stopped by as I was about to leave to buy take-out at Boston Market. Dad invited all of them to stay to eat with us; he loved Boston Market. Well, off I go to Boston Market with 7 orders, and it was 18 miles away. It wasn't dad's money that got spent, it was mine. My gas, too. And the time I had to run to the medical supply place and buy different catheters. And tip delivery people. These expenses do add up. He never thought to reimburse me, though when I first moved in, he gave me $100 for groceries. When it was gone, I paid for them so that he and his caregivers could eat. I was out of the house by then.

These are minor expenses, right? But when taking into consideration that I was taking care of him and his business instead of working, the loss of income added to miscellaneous expenses ended up being quite a bit to spend.

Prepare now so you won't regret later.

Take your pre-construction, pre-move in total and subtract that from the post-construction, post-move in total. Then divide that by 12. That gives you a better idea of her actual usage.

If you cook all her meals and she eats with you all the time, make sure to factor this in as well.

If you drive her around make sure to charge for some gas.

Or else you can have some of those costs paid by ACH directly from her own checking account (like cable) and her Medicare/healthcare (and set up a portal so you can pay her bills for her directly from her checking account online).

I personally would not feel bad to charge her. This isn't taking advantage of her or gouging her... these are fair living expenses. Her living with you (and thus having a 24/7 caregiver) should not cost you/your family. It should be hers to pay. This is what every elder saves their money for when they retire.

We bought my Mom's house (FMV) but she still lives in it. We don't make any money on the rent we charge, it is all pass-through (taxes, utilities she doesn't pay herself, insurance, maintenance & repair, etc).

FYI when an elder qualifies for Medicaid it is usually because they require LTC (so, immobility, profound health issues). This program is what "takes" 70% of SS. Don't fear this... if she's in LTC she won't need the other 30%. We're going through this with my own MIL in LTC on Medicaid here in MN. She gets great care at a great facility in a private room.

What will you do if the caregiving becomes more than you can handle? This is a common problem for many adult children. Burnout is a real challenge, so please read some of the posts under this topic. Bless you for taking such good care of her.

She has dementia, and it will progress. Someone will need to provide the services she needs. Getting her to the toilet, showering her, making sure she doesn’t wander.

Are you prepared to do such things, and if so, will she pay you to do them?

For me, what she brings in a month would be what I would go by. I think she should pay for her cable. If a landline, she pays. Any special food she wants, she pays. If you want to split utilities do that. She should be paying for the extra taxes for the remodel. Anything for her she pays for. Thats premiums for insurance, that includes home if it went up because of the remodel. But since she paid for the remodel than I can't see charging her rent. You really need something in writing that she agrees with all of this and for that she needs to be competent. Understand what she is writing. I may see an elder lawyer for that.

Another problem, by remodeling your garage, I hope she will not need Medicaid in the next five years. If so, Medicaid looks at that remodel as a gift to you and will cause penalties. Medicaid feels you profit from the remodel when u sell ur home.

My personal stance is if you do not need the money let her save it for her own needs and care.

If you do need just take the amount you need to get to the place where you were before she moved in terms of expenses.