Depresiion or allergy? Shall i consult.

My brother is having mucous coming out from his nose for almost more than three years.Also, he will not like to go outside,  be in the room all time.He gets so irritated seeing someone is dirty, listening their talks n if they talk on phone.He feel very weak n sometimes will not able to breathe due to a lot of mucous coming out.We already showed him to doctors in Bangalore, but no improvement.We do not know if this is due to depression as his business is not working proper for two- three years or he is having some allergies.Sometimes he says he is able to see some virus coming towards him from dirty areas n other people whom he does not like n itching will start in his body and mucous will start coming out.He has also become superstitious carrying stem of shami plant n thinking it will cure him.Can anyone suggest please whom shall I consult.