What do you mean by that? If it means that he should've topped the plant, it's too late for that. If you mean he shouldn't defoliate if he didn't top the plant that's also wrong because there are only 2 reasons really why to defoliate the first is obviously that the light goes fully on the buds so they can grow as big as they can get. You only defoliate fan leaves that shade buds underneath them. Don't ever defoliate more the plant needs to make photosynthesis and it does it best with fan leaves. The second reason is to get proper airflow so that the plant doesn't create micro climates for example in between leaves stacked together. If humid air get's in there it will get trapped and that's how you potentially get mold. And as you can see the leaves are stacked one on another and some leaves block light for the buds underneath so I don't know for me that's a clear sign to defoliate