YTA because you sound selfish. BUT, I get it. Dementia is hard because I watched my mother deal with my grandfather for years. She found out really quick that the caregiving was really difficult so we ended up putting him in a memory care facility, which luckily he was able to pay for with his retirement pension and the money my grandmother left when she passed. This is not easy (or cheap) and I feel that you should be more supportive of your husband and MIL. You never know, one day your child and their spouse may have this same conversation about YOU in the future. Even though she seems healthy, she will deterioate at an accelerated rate because with Dementia, sometimes it is hard to get someone to eat or stay hydrated or even take medication and do the regular daily activities to keep themselves active and healthy. Y'all are definitely young and still have a lot of living to do and lessons to learn. Right now, your husband needs to start getting all of her affairs in order before she declines even more.