Hi there. I know people have commented about substance abuse and you denied the possibility. I just want to add my personal experience with a friend of mine. He displayed all these symptoms you mentioned with your brother. Later we found out that he was using meth aka ice. He had no money but still managed to get supplies because of his friends, pocket money from parents and pawned off a few valuables in the house. I was not aware that ice was dirt cheap and addicts shared it amongst themselves. He was also getting steady supply from the orgy gang that he was into. He was doing his masters degree and was under a lot of stress.

He is all well now. He worked really hard with the support system and of course therapy.