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 (one who practices at a site with a medical school). He or she is more likely to be on the cutting edge of their field and more willing to order specialized testing to get to the bottom of this, as well as specialized treatments to help your brother better manage his symptoms.
If you have any additional questions about this, please let me know.
If there are no additional questions, a positive rating would be appreciated.
Best wishes to you and your brother. God bless.