How do I find out from the council about housing?

I'm 31 yr old female seperated from my husband, no children unfortunately and living by myself in my relatives empty house which is for sale whilst she is in a nursing home. I said that I would reside her to look after the house for her. The fact is, after she dies, or if the house sells, I will have nowhere to live as I am currently unemployed, with no money. I know I need to find a solution to this problem, and need to enquire with the council - I just don't know the system and how to go about it ?