If a divorced spouse needs a nursing home yet the house is still in both names how does it work?

we have been divorced for 5 yrs my ex is 23yrs old then me and we were married for 28 yrs. He asked if he could stay in the house till he could anymore and I agreed. I have been paying 1/2 the mortgage & the house insurance. I also help him in shopping and cooking once a week. the mortgage is a 30 yr and we are only 9 yrs in we also have a second mort on the house. we are upside down in the house. If he was to go into a nursing home how does that affect the house and me moving back in. I pay 1/2 with the thought that one day I can have the house, I am just getting worried that I will end up losing the house or that the county will take it due to my ex being low income. he is and has been house bound for a while now but it is getting worst.