I think he is out of his depth at the moment, but he could grow into it, IF given the time, but time is not what he has.
He needs to start re earning the time as right now hes on borrowed time. hes cost the Glazers 10's of millions. I doubt they are considering giving him a free ride. The only reason hes here still is out of respect for SAF imo.
Results would suggest he is & that's what managers are judged on. He's only still in the job because he was anointed by Fergie imo. If he'd have been at any of the other top 3, he'd have already been sacked.