I was saying he sounds as if he has Bipolar disorder. Bipolar and Manic depressive are one and the same.
He is probably Not a paranoid schizophrenic unless he is dillusional and it doesn't sound that he is.
If he is just obstinate, argumentative, nasty, and sometimes funny and extremely intelligent and interesting and creative.
I'd have him checked he is more than likley Bi-polar, Or Manic Depressive.
And as much as I dislike the Psyco peeps.
They have Nailed this disorder and it is treatable
He is your Brother and if the tables were turned you would want him to help you.
This disease is EASILY treated.
Get your family to help.
Back when my brother went thru his highs and lows he was considered crazy, by most.
Bipolar disorder is just a chemical imbalance.
GET HIM HELP HE IS YOUR BROTHER FOR GOD'S SAKE