To be clear, he did ask two questions with opposite answers...
1. Can A40 come back in the game for A32.
2. Since we have not had a live ball and A40 left the game does he have to sit out one live ball if Team A has other legal subs.
#1. No.
#2. Yes....almost. It is not "one live ball". You could have several live balls without the clock starting. A40 must sit out until the next substitution opportunity after the clock legall starts.