He would say that really, wouldn't he. He had loyalty to the player. If he's asked about it there is only one party who's case he is likely to advance.
The interesting thing is that when/if he becomes manager his loyalty will be to himself and his own backside. He won't be dying on the Donny van de Beek hill.
People are probably not wrong in that he's more likely to be given a shot, but I don't think we're going to see a large degree of patience shown just because he's van de Beek, Dutch and played at Ajax. If he had such faith in Ajax he'd buy most of their first team, but logic suggests he won't do that.
Donny has to cut it in the PL first and foremost, can't expect the manager to line it all up perfectly for him. He needs to massively step it up and take more responsibility, this perfect system for him might not be arriving at Man Utd in the next few years.