[BubbleFunker]

I have heard that certain strains of mj may cause an exacerbation of mania, in some people with Bipolar, Psychosis and or Schizophrenia. (Note the underlinings.)

But as it is with many herbs and medicinal preparations, there may be side effects.

So, if your brother is having "side-effects" he may wish to either try different strains (some sativas can cause increase in mania, in some people) or simply not use it.

Cannabis is good for some people with Bipolar, and not so good with some people. I mean, if you're allergic to peanuts, and they say peanuts are good for everybody, how are you to feel? There are no absolutes.

Not enough sound research has been done to draw any conlusions from. Thank-you FDA, and US govt!

There is evidence demonstrating that Lithium is still the most beneficial for Bipolar, though. Has he been tried on it?
Most of the anti-psychotics have a myriad of side-effects, bad ones: weight gain, raised glucose-->type 2 diabetes, headaches, suicidal tendencies, etc.
You have to weigh the pros and cons of all suggested meds vs. the condition itself.