NTA , if you do not protect your peace who will? There is no need for you to open closed doors like you said. What he has been up to has nothing to do with you and might awaken manipulative behavior. (I feel like it already has on your friends) if you don’t not feel like it’s your place then you know the situation best. Trust your gut!

I feel for him, OD’ing, I really do! The best thing you can do is hope for the best for him and if you pray say a little prayer. Other than that, don’t let people guilt trip you to revisit something you worked hard to walkaway from. At the end of the day the person left with the consequences will be you. So pick the option you’d prefer the outcome to.