Not stand in his way, and asking for a lot of money is different things. I mean, I doubt that Mourinho will say, no, we won't negotiate for De Gea, suck it up. But he might ask for the maximum amount of money we can get. Buffon went for 53m euros 15 years ago, De Gea is a similar caliber of keeper so now he should cost twice as much.
We played hard ball with Everton for Schneiderlin. We made it clear that we'll sell him but at a respectable fee. I hope that we ask for at least 100m euros for De Gea. We don't need the money so no need to sell him cheap.