Ironically enough, I think the person with the most to lose out of all this is Lalo Diaz. Frank is in the twilight of his life and career (might not even practice anymore for all I know) so besides leaving behind a questionable legacy isn't going to hurt him much, except his ego. Diaz on the other hand you'd have to think stands a very good chance of losing his job over this. Supporting a fraud and making aggressive and snarky comments when approached for comment isn't going to go down well, would be shocked if there wasn't some sort of investigation happening as we speak. He unquestionably knew Frank's claims were false yet allowed him unfettered access to the kids, not a crime of course but allowing someone with such demonstrably poor character to coach at (from what I can gather) a fairly renowned school is not a good look. Couple that with his responses to Derek and others and you'd have to question whether he has brought the school into disrepute, a standard employment clause where I'm from, can only assume it's the same over there. For that reason I don't think Frank ever 'fesses up because if he does, chances are his good mate is going down with the ship.