Search around the Web for some humor about relationships and at the end, tell him how sorry you are this happened and offer to help him create a profile on eHarmony, Match, etc. to get him back in the saddle.
As a guy, I’m less about having someone comforting me, and more about having someone solve my problem. After all, if you have a girlfriend, are married, or have a serious relationship any sympathy you offer him is going to come across as vaguely fake because, of course, “what would you know, because you have a girlfriend/wife/etc. who DIDN’T dump you right before Christmas”.
Just keeping in touch would be a big deal. When I was in college, I went through a traumatic breakup right after New Years, when all my friends and roommates were gone but I was working and couldn’t stay back in my hometown. It meant the world that one of them called and said “Hey, I heard about this and it sucks.”