What do I do with my MIL with Crohn's who refuses to wear protective undergarments?

You've tried to keep up with the clean up and you've had discussions with your MIL about this. What was the tone of the discussions? "Please, you have to wear these" type of discussions? You may have to get really, really blunt and tell your MIL that she smells, her clothes smell, and her environment smells and that you feel bad for her because you know how difficult this must be for her and that no one wants to be told that they leave a cloud of odor behind them. When my dad stopped showering I tried all kinds of things to get him to take a shower but it wasn't until I finally told him that he smelled that he got into the shower.

Before your MIL leaves the facility can you enlist the help of the social worker and sit down and talk with your MIL together and let her know that if she refuses to wear the protective garments that she may have to stay in skilled care because having stool over everything, on everything, and on her is a serious health hazard? I also think it's OK to tell your MIL that you are sick of cleaning it up. You could say something like, "Mom, I clean up after you all day long and I'm frustrated because you don't seem to want to help me. We live together, we're in this together, but I need your help." I've always been a huge fan of the "Help me to help you" approach as it always worked with my dad.

I'm assuming that she doesn't have dementia since you didn't mention it. All of this will only help IF she doesn't have dementia. If she has dementia you will probably need to come at this from a different angle.

Good luck, Cricketfarms!

Have you tried something like the Kleinert's panties or the Health Dri types. They are very expensive but if you buy one or two pairs, then you can put something like that on her and maybe she will keep them on since they are similar to cloth underwear.
When we tried to get my mom to use the Depends she fought us. She was living with my brother and sister in law and my SIL was having a hard time getting her to use them. My mom would put the Depends over the regular underwear. My SIL still had to wash the regular underwear because it got soiled but I suggested that I would just buy my mom new underwear if my SIL didn't want to wash them. Finally my SIL was able to get my mother to use the Depends only.
I am so thankful that I didn't have to go through this fight with my mother. I know I would personally fight it myself. My mother is now living with us and I will give her new ones to put on daily. It is a relief not to have to clean up soiled underwear.

Good luck to you. It's a tough fight.

Thank you for your answers. She does have dementia, on top of some pretty significant mental health problems she has had all her life. She is very narcissistic and manipulative, not to mention stubborn; none of which are related to the recent stroke. I did have the fairly blunt discussion that I could not continue to come in and clean up after her indefinitely. I said I knew this was a difficult time for her and I understand she can't help her condition, but I asked her to please help me and also help her son out by wearing the protection. She suggested I simply hire help. Well, that doesn't work (we have tried previously) because she won't get along with anyone else and runs off everyone around her with her attitude. The carpets in her home that she used to take such great care with will have to be replaced they are so stained with filth, even though I have cleaned them thoroughly. Her son has also had the discussion about having to stay in nursing care if she won't cooperate with wearing the undergarments (I don't like to call them diapers because that seems un dignified). But she is otherwise physically in fine health, so am not sure she qualifies for long term nursing care. I just can't get past how someone could prefer to spew diarrhea on everything they come in contact with than wear a protective undergarment. I would wear a suit of tinfoil if I thought it would be of help to my children. Just thought there might be some magic phrase out there that would help the situation.

Sorry, don't think that "magic phrase" exists. My mother was pooping diarrhea in the car and on all her furniture and she denied it ever happening.
We ended up not giving my mom an option. There was no underwear available for her to wear except for the Depends. Like I said, maybe if you tried one of the cotton ones that are washable she might be more open to that option.

I switched my mom to Depends about six months ago. And Pink is correct, take away all the fabric underwear so she does not have a choice. If she has dementia, eventually she will forget there is even a difference.

This may not be an very helpful suggestion but sometimes something in the absorbent part of Depends( and I use the brand name as a general description that than a brand recommendation) I too prefer not to use the term "'adult diapers" Try putting a pair of plain cotton underwear under the Depends. Make sure the perineal area is kept very clean and a good barrier cream applied after each change. if you have not experienced it you have no idea of how caustic feces is on skin. It burns and itches unbelievably. If you have to force the issue use the depends with the side closures. Snug them up and then use duct tape over the material round the waist with the ends at the back where she can't reach the ends and hopefully not get them off. I don't expect her to like it anymore than you like cleaning up after her. Can you pull up the carpet and replace with vinyl so it can easily be swabbed cleaned. As an aside I have just spent two weeks in hospital with uncontrollable diarrhea and I can assure you I was very thankful for the protective underwear but I don't have dementia - yet!
Home and better now.

Since your mother is narcissistic and manipulative, would any kind of talk about her health and the health problems she could get from the ecoli in feces sway her? I'd play up that it could make her ill and affect her good looks or whatever she might be vain/proud about. Because it IS a health risk to have feces everywhere. Or that others might smell her and think she wasn't clean...something along those lines that would appeal to her sense of personal vanity and pride. I'm so sorry you guys have to go through this. Is there no way to adjust her diet so she's not having so much diarrhea? That can't be good for her health over the long haul (or for your health for that matter).