The Seagulls keeper shone as Holland defeated Poland in their group clash earlier this week.
"On a day to day basis, he's brilliant to work with,” said Stern to Brighton's website. “He's a coach's dream in that sense. He turns up ready to work, wanting to learn, wanting to push boundaries. He's about as good as you could possibly work with.
“He's always got something in his mind that he wants to improve. He takes on ideas that I or the head coach might have for him and he’s very good at adapting to what's needed of him.”
He continued: “He's incredibly good with his feet and has the ability to execute passes that only the top goalkeepers can execute and also the vision to see those passes.
“But he’s also got all the attributes of an old fashioned goalkeeper, if you like: stopping the ball, making saves. He's good coming for crosses and defending his box. He's dominant and good at defending the space outside his box as well. He doesn't really have a key area of weakness. He's got lots of things that he needs to keep working on but there's no area of his game that's really lacking.”