There are any number of things or a combination that could be going on with your brother. It isn't our place to diagnose here though. I agree that he needs to be seen by a professional. Obviously, he is in a lot of distress.

My parents also didn't want to admit that mental disorders warranted treatment - they thought they could ignore it and it would go away, or the person should just shape up and act normal. There are any number of reasons why people avoid treatment for mental disorders, including stigma, the belief that it should be healed through spiritual means, or just flat-out denying that they are legitimate diseases. In my family, 4 out of 6 siblings have had anxiety and/or depression, 1 is schizophrenic, and 1 has Down Syndrome. My parents started out denying that Down Syndrome would have much effect, but as my youngest sister is pretty severe, and has always had physical complications too, they didn't have any choice about accepting that. Later on, when my brother with schizophrenia became unmanagable, they eventually had to admit that he needed treatment. Most of the rest of us (I guess mainly me perhaps - I'm the oldest) had trouble getting taken seriously, and that made things worse.

What it comes down to is that denying the problem makes it worse, not better, and that many factors are involved in mental illnesses, just like many factors are involved in those illnesses thought of as physical. The two are not separate entities like our culture likes to believe. Both types of illnesses have biological, psychological, social, and spiritual factors. If God can heal mental illnesses, then He can also heal physical illnesses. I believe that he can (both), but that He requires us to work on them ourselves and do what we can to get better. That means getting treatment, as well as having faith and taking care of ourselves, and social support helps also. If your brother had a broken arm, would your parents deny him treatment and expect God to heal it? You have mentioned that your brother has symptoms that he perceives as physical also, such as numbness in his extremities. It's all connected, and it is real to him. And we don't know enough about the brain to say that negative results on a brain scan mean that no physical problem exists.

Your brother is lucky to have you to advocate for him. Good luck to you! And please let us know how it's going. I think that eventually your parents are going to have to start listening to you.
Wendy

<font color=orange>"If we are going to insist that people pull themselves up by their own bootstraps, we must ensure that they have boots."</font color=orange>