Maybe you could anonymously let the people he’s trying to mentor for know of his unwholesome behavior?

See, that would be an okay idea, but they’re not going to believe it. He’s a recovering alcoholic (he’s a dry drunk though, he was knocked out for a few months after an accident so he couldn’t drink instead of deciding to quit and work through the recovery process) so in their mind he’s a changed man. It doesn’t matter what I say, if it’s not currently happening and they can’t see it, they won’t care b/c he admits to being a “less than stellar father” in his words but he won’t go into details and he won’t admit it was his fault. They’re much more likely to believe their buddy than they are to believe me.