Hi there. I'm Dr Bob and I would be happy to assist you if you still need help.
I would be happy to try to help with your questions. I've read your post and was left with the impression that your brother has seen many doctors. Do you know if he has seen an immunologist? Do you know what treatments have been tried? His type of case can be very difficult to diagnose precisely and manage effectively, and likely will need an academic immunologist willing to order more specialized testing and treatments.