He's been working with Katie Agresta since at least 1990/91, maybe even earlier than that. I have a clip of her on Entertainment Tonight talking about her clients and she mentioned Jon (and Richie too, I think). So I think it's just a safe assumption to make that he's still working with a coach, whether it's Katie or/and someone else. If you go to her website she has Jon, Richie, Dave, and Alec on her list of clients. In fact, she has David listed twice.