Well tell him its another part to life. & more and most people have been through the same thing. He can make it, and there will be other people for him to meet. Then take him out to a social thing. Movies with a group of friends. A big dinner.
I agree with @ransoms, the best you can do really is just be yourself, and help him keep his mind off it. Maybe doing/talking about stuff you would normally talk about will help. He knows that you feel crappy for him, acting normal will help him forget about it a little easier. That's most likely why he would even contact you right now- for a bit of sweet releif from a good-old mate.