Unfortunately, I witnessed a very similar situation with a distant relative of mine who was clearly not mature enough to live on his own, despite his elderly age. His house looked exactly like that, with the exception of a few half full gallon jugs sitting around which he used to urinate in.
My dad ended up giving this relative a choice which he accepted. Give your house to me (semi detached), I'll spend the money out of my pocket to fix it up and sell it, and you come live with me and have a clean bathroom and 3 hot meals a day. So in essence, my great uncle handed over a crappy house to my dad that was on the verge of being condemned and now lives in an almost brand-new home with my dad, step mom, step sis, etc. I consider it a good deal, especially since he isn't really fit (health wise - **** cigarettes) to be living on his own.
His house was condemnable. My dad gutted it completely, spending nearly 40 grand out of his own pocket to fix it up. He ended up selling it for 52 grand, so he made some profit on it, but he also put an intense amount of labor into it over a few month span.