SaxonRider is on the ball I’d say. Go and get your Bro, get him assessed ASAP when your back. Don’t let him or yourselves fear hospitalisation. They’ll look after him and it will give him a chance to recover. Be there for him but don’t try to fix him. It will happen eventually but it may take a while if he’s as ill as it sounds.
Good luck to your brother and yourselves. ?