The best plan the profession has at this time is to medicate carefully – meaning insightfully and experimentally – to get his autonomic nervous system stabilized at a more moderate emotional set point and lower threshold of stimulation (see the thread I stared on the dangers of drugs for bipolars; see Recreational Drug Use is Dangerously Different in the Bipolar Brain).
Once that is accomplished – and it may take a while – he can be introduced to the mindfulness-based cognitive therapies (see two posts above). If he is compliance-resistant, however, you will need to get with experts you can probably reach through his Rx’r to get that handled. Unfortunately, the laws in most states require a parent to get a conservatorship on an adult child to enforce medicinal compliance. It takes a while, but it’s often worth the effort when the adult child is out of control.
But we do have Invega paliperidone and other long-acting anti-Ps now. If you can get him on one of them, you may see some progress.
I know I seem to be flipping back and forth here, but I have to add that many sz pts are so paranoid, they see IV administration as an intolerable threat. Good luck. And get help.