It all depends on what the manager is asking the keeper to do is he asking him to be the sweeper or are the defenders pushing to high and hoping De Gea is there to cover them. By the way Spain play I'd assume they want De Gea to be doing the sweeper keeper role. The way Spain are being caught out having De Gea sweeping wouldn't solve that.
De Gea made 1 mistake against Ronaldo but I think he had one or two in the warm up games so he is a bit under pressure and the fact he's been out of Spain so long means he doesn't have the cheer leaders in the press to defend him.
Nothing has been officially announced but there were rumours that a deal is agreed in principle and will be signed before the start of next season but there were other reports saying he wanted to see how the start of next season went before signing because he knows the next deal probably shuts the door on Madrid forever and he wants to make sure Utd are going to try and take on not just city but also Madrid and build a team that can win european titles.