“What if I know someone is doing things that are wrong but he is still passing the sacrament and going to the temple? Should I tell his bishop?” New Era, May 2014, 48
If you have direct knowledge that a person is committing transgressions that might disqualify him from passing the sacrament or going to the temple, you could talk to either him or his bishop about it. In either case, don’t use an accusing tone or call the young man a hypocrite, but speak kindly and express your concern for him.
Talking to him privately would give him a chance to own up to his behavior and begin repenting by going to the bishop himself. If he refuses to listen, or if you feel uncomfortable approaching him in the first place, you should talk to his bishop about it. The bishop has a special calling to watch over the members of his ward and is the president of the Aaronic Priesthood in the ward, so he has a unique responsibility for this young man and is in a unique position to help him. You shouldn’t talk to anyone else about it, because that would be gossiping, and that doesn’t help anyone.