From what you have described, you are working in a situation in which you have to walk around on eggshells to a certain extent. He drinks all the time and sometimes "flies off the handle". Umm: That's really not okay. Despite how things are 'set up' right now so that you can continue taking care of that lady, You still worry about "what he's been told" and whether or not he will stay away from you. You started out by stating you were in love with him at one point in time, but no longer are.
Maybe the first lesson you can get out this whole experience is don't let yourself fall for a married alcoholic man who is related to someone you're supposed to be professional with. We're all human and sometimes we just fall for people. So, what needs to happen to safeguard against things escalating to a nasty outcome, is you need to know where your boundaries are or where your boundaries should be. This is partially an ethical and moral issue. You've got to learn to have the mindset that there are just certain lines you can't cross, even it is just with your heart and mind. Don't go there. For example: married alcoholic men are off limits.
But: There is also the issue of your sobriety. There are certain situations we need to pull ourselves away from. It sounds like you're spending too much time worried about what he might do.
Past behavior is a pretty good predictor of future behavior. Realistically, unless he gets sober himself, you can safely expect him to "fly off the handle" again.
This just keeps getting better. Now you say he's a narcissist who will make you out to be the crazy one. Not good, Brenda, not good.