Complex sentence: After everyone watches home videos of Victor, Nigel finds Charlie there and asks him personally to make his face look like a tuba player's face, and begins wondering if Charlie is really a tuba player.
Split into simpler sentences: After everyone watches home videos of Victor, Nigel finds Charlie there and asks him to make his face look like a tuba player's face. Charlie's response leaves Nigel wondering if Charlie is really a tuba player.