It sounds like he may be developing some health anxiety. So, he has already been to a Psychiatrist and it did'nt help? Maybe you can get him in to see a therapist that deals with health anxiety. Yes, the ear problems could be causing his fears. It sounds like he's scared it could happen again. This makes sense since he's never had any health problems before. The ear problem is all new to him.
It appears that your brother has developed some OCD and anxiety involving his health due to the experience with his ear. See a different psychiatrist as the one you saw is worthless. There are medications available to help with all of this as well as therapy. Google "free" or "low cost mental" health care clinics in your city and just start calling them. Normally if one can't help you they will know who can. Your brother needs some professional help as this won't get better on it's own. I wish you both all the best.