I’m so sorry you are going through this, it sounds incredibly upsetting and distressing and I understand why you passed out from “overload”. You are undoubtedly overloaded and burnt out from all of this chaos. Long term meth use can lead to violent and aggressive behavior, confusion, delusions, paranoia, psychosis, and suicidal thinking. He certainly needs professional help, and if you can try checking out SAMHSA Treatment Finder - they may have resources for state funded treatment.
My biggest concern here is safety, for you and him (and others). Because he is so verbal about you not calling the cops it may be a good idea for your safety to call them, or even go to local police station, when he isn’t around as a way to prepare and protect yourself. Tell them he has a gun and is under the influence of meth and you fear for his life and others. Give them details of his history so it’s all documented. It’s always better to be PROactive versus reactive and scrambling for help in the moment. The Family Violence Helpline could be a resource that could help you (800-996-6228) and your family.
It’s probably a good boundary you set telling him to leave home at this point - it just doesn’t sound safe. Knowing your limits is part of being aware and having reasonable expectations - this allows you to work with your family instead of being surprised and shattered by them. The conscious act of recognizing how much you can stand makes your situation more predictable. Awareness won’t change your circumstances, but it allows you to anticipate what’s coming and plan for it as best as you can. With awareness (which you already have a lot of), careful self-assessment, and practice, you can continue to work on seeing your limits from a safe distance and even use them as guides.
If possible, do your best to find an Al Anon meeting where you can meet other families going through similar struggles and hopefully they can share resources that may be helpful to you. At the very least you won’t feel alone. By reaching out here you are making progress in getting help for you and your family. I know this may be redundant but, again, if you EVER feel you’re in danger or he is a danger to others the best option is to call 911.
Thinking of you and your family and hoping for the best