He told the Sunday Sun: "For a young lad he's been through a lot already. I think there have been times in the past with England, and in a couple of the recent games, when he's got some stick from people I would have expected more of.
"But he's been strong enough to deal with that, and one of the things when you play for England is, it's not just about going out and playing, it's dealing with everything that surrounds it.
"If you're big enough, and prepared to put your head above the parapet and take the flak, knowing the reward of playing for England is just fantastic, it still takes a lot of bravery to get out there and take the ball and be bold enough to play in front of, not only the crowd but ex-players that are very critical.
"The spotlight with everything with England is huge, so dealing with that can be difficult. But Stewart's growing, and getting better all the time."