True. IF H were to cast Therapy. But he doesn't have to.
H should cast Mage instead. I think H should try to not cast Therapy at all.
Only if U Therapies a creature away, H can Therapy the Chatter.
Yeah I edited my reply, didn't see yours when I posted. If H never casts Therapy he gains 3 life and can win the race, so U is forced to draw.