Talk to General Physician on Vaham ( Delusions)

Assalam-o-alaikum! I'm medical student and am asking for my brother. He has been sick time to time from last 2 - 3 years. Minor sickness like stomach problems , BP issue , High fever sometimes . But whenever we ask him to go to doctor he afraid too much. And he thinks that he is having some disease. He don't take medicines just bcz that they will cause another disease. He use to check BP , Temp for 8-9 times a day if he suspect something. I want to ask that if he really need a doctor ( psychiatrist) or you recommend something else??