I guess you create your own judgements based on results. If a thing seems to be helping, support it. If it seems to be counter-productive, challenge it. You'll be right more often than wrong. There's his side, her side, & the truth.
If he's saying he doesn't understand tell him to ask questions until he does. Not understanding is not helping and not paying attention is not helping. Also teach him to doodle quietly on his notebook so he can sit still & listen, maybe.

Youth lives by personality, age lives by calculation. -- Aristotle on a calendar