I told you, he's more than ready and just needs to play.
He's 19, has never played at this level, he's not fantastic defensively and not really suited to play under Mourinho. He's going to have a few bad performances along the way too but right now he's already better than your other right backs, he just needs to play and he'll 100% make it in the long run.
He can add more offensively than he has, he's a bit timid at times so far. He tends to go forward a lot more often and scores plenty of goals for a fullback.