I don't see what you're talking about, quite the opposite. He spent more time helping them than his normal team. He carried out the assessment fairly by treating them at the same calibre as his current one.
My first step onboarding new people is to make sure an experienced dev helps the new ones make their first commit. He didn't even get them to that point. It's primarily a bad leader/manager, not bad workers that create a problem.
Onboarding a remote team is a major effort which needs to budgeted. That should have been clarified during the sales process and given to the manager when starting the task. Of course also the manager should have raised it when getting the task - if we do this right it means we won‘t deliver x, y, z as planned but instead he used this lack of planning to let the effort fail. None of the parties dealt honestly and in a straightforward manner with each other so discussion of morals is not going to yield much. Often in such situations the incentives are not aligned and the first victim in war is the truth.
