I know he is very sick and vomiting and pooping blood, but encourage him to do some basic stretches if he can. Basic neck exercises to increase the flexibility of the neck and other few basic YOGA stretches.
A lot of health problems could be due to nerve impingement. Taking pressure off the nerves can make miraculous difference. I am not sure if Inversion therapy is suitable for your brother, but investing in any "yoga sling" to help your brother stretch his spine may be beneficial.
My 2 cents.
PS: Pls dont think I am asking you to take your brother to a chiro. But it could be a spine related issue which could be helped by putting the vertebras back into place.
Good luck