Dear Shaun:
If you do speak to him about it, not when drinking beer or any sort of alcohol. Better be sober for that and better maybe not be alone in a room with him when having such talk, but be in an open space, maybe a bigger living room, maybe outside, maybe in a public place.
Why do you think it may be a better idea to leave things unsaid?
I think it is better to tell him that you are sorry for what you did, tell him the specific behaviors you are sorry for, over how long you did those behaviors, that it was wrong of you. Don’t excuse your behaviors when talking to him, telling him you were or are mentally ill and that is why you did these things, or any such thing. Instead be factual, give him the facts: what you did, and that it was wrong of you, that you regret it and feel very sorry that you did.
Let me know your answer to the above question. And if you do choose to tell him what I suggested, you can practice by typing it here first, get my feedback, and proceed from there.
anita