Welcome to the community here. I am really sorry to read about your situation, it certainly sounds like a difficult place to be in.
I'm not really sure what to suggest! All I can think of is that you could call the police and seek advice. They may be able to put you in touch with organisations that could help. If your son is becoming aggressive and is on drugs, he could be unpredictable.
The Beyondblue help line on 1300 22 4636 may be able to make suggestions as well. The support people will certainly listen to what you have to say and can offer ideas.
It is very hard to get someone to seek help for themselves when they refuse to do so or don't feel like they need it.
If you are really concerned for his safety and yours, I would be considering calling the police and ambulance to assist and he could be taken away so he can receive help.
You need to look after yourself and your partner.
Hope you are able to find the help that you need to sort this out. Keep safe!
Cheers from Dools