Lucidity, my husband and I are in a similar situation. Our son has had several episodes of being delusional and had to be hospitalized because of it a few times. He's gotten violent on several occasions in the past. Thankfully he has been able to control himself and there has been no physical violence for the last 2 1/2 yrs, BUT there are some other conditions going on (currently) that worry us and are not good for him . We are a little wary of confronting him on these issues while he is not currently doing well mentally. I totally agree with the advice AlphabetSoup gave, SAID: we need to "try to remember his actions aren't completely him- he's responding to whatever he's experiencing in his head". Yes-It can seem like they have become a different person; not the son you know and love. Of course YOU certainly need to take steps and do what you need to do to keep yourself SAFE. If you ever DO find yourself needing to request help from the police dept.(Hope you never have to , but it happens.) I would recommend that you make sure to tell them before they even arrive that you are dealing with a family member that has been diagnosed or may be having delusions. He'll likely be taken in for a psych evaluation at the local hospital. I would not recommend doing this however unless it is an absolute emergency situation and someone is in real physical danger!
I am sorry you (and your son) are going through this. It can be overwhelming even when there is no violence involved, because you worry for their future; wondering what to do, if or how to help. Like you, one of my biggest worries is what will happen and how my son will survive when we're no longer around. We live in an urban area where there are so many mentally ill and homeless out on the streets.