Dee, although late to this post, my prayers are with you and family, too.

It's difficult to create boundaries when another enables and perpetuates the destructive behavior. I've family members like that and have difficulty w/ boundaries b/c the heart interferes. Recently, I've had to let me nephew go, no more birthday gifts, Christmas, etc. None. (I know my mother will attempt to interfere, but no). Why? He lies, steals, drugs, constant job change over, went through and has nothing to show for his $20K trust fund w/in 90 days, wrecks cars, steals cars, foul language, disrespectful, disappeared for weeks at a time, damaged personal property, made threats, etc. He's only 20 and his mother (my sister, is a horrible parent - which is why only one of her four children live with her). Although not entirely, I do understand your situation. I say no more. I'm cashing in the savings bonds I purchased for him and sharing with my parents (his grandparents of whom he stole money). He's not earned it.

You may need to do the same. Say no. Don't spend a dime nor a thought on her. Don't invite her to your residence. Should you attend a family function where she is a guest, don't acknowledge her. Your MIL has enabled her, it is entirely her problem. Allow th entire burden on her, mayhap she'll 'learn' her mistake?