I remember going into my husbands bathroom after he had moved out to clean it. It was disgusting. His drinking at that time was at an all time high, and it seems like the first thing to go was cleanliness. The tub and sink were a nightmare, and I'm pretty sure those were vomit spots on the wall.
My X is a pretty tidy guy. Very vain. When ever he left the house he looked good. He kept the parts of the house he shared with my daughter and me picked up. But his bathroom and, to a lesser extent, his bedroom were a mess.
My heart goes out to you (and your brother). You're in a very difficult place.
Good luck to him tomorrow. I'll be thinking of you both.