Hey fiona
What an awful situation, and you were just trying to help.
Your brother is clearly a very unwell person, and the things he is talking are extremely hard to overcome.
The first thing you need is support for you. Whilst he has problems and is your brother you dont have to tolerate aggression or anything else, especially as you are trying to help. Woukd you be able to sit down and give him an ultimatum?
By the way Na meetings are still on, just on zoom
Hope you write back