My wife is struggling to cope caring for her parents. FIL is slow and MIL is bedridden. They refuse any outside help and won't consider moving. Any suggestions?

Nickname: You're wise to recognize that your wife will not be able to continue to be the panacea for her elderly parents. Her parents are going to have to locate some other ideology because your spouse cannot be 'their chief cook and bottle washer,' else she drops over from exhaustion.

If they won't listen, she needs to just do what she can and leave the rest. My parents don't listen either.

They CANNOT continue to refuse outside help; one family member cannot do it all. Talk to them about what you’re willing/able to do and tell them you WILL be hiring outside help. Period.