Congratulations on your DGS starting University.
It is a very emotional day, keep the tissues handy. Expect mixed emotions for you too. But I would say to him "You're dad would have been proud, you're dad is proud." Do it with a hug and not as you are leaving so that you can leave him on an upbeat note. It's nothing he's not thinking and feeling himself. Boys are very complex creatures and we always have to look for the sub text with them. But hit the nail on the head with them of what they are worrying about and you get a stream of talking, in my son's case anyway.
And no, you won't embarrass him. He will be very glad of your love and support, especially when you have left and he thinks over what you have done today. Take him with pride, he's done so well, hug him in private, have a word about his dad and leave him saying you'll expect him and his washing in a month. (They told my daughter not to go home in first month so that she could acclimatise, that's what she told me anyhow
)
Good luck, thinking of you. 