[Ghoulish Delight]

Hmm, I think you should let it go, or just talk to the mother for information's sake. Don't intervene. I remember the splits I had with my friends at about that age. The LAST thing that would have been good for me would have been our parents getting involved. It's going to happen, and that's the age he should start figuring those kinds of things out. Either figure out how to mend the relationship, or learn how to accept the fact that sometimes friendships end. Unless things become destructive, I suggest letting him figure it out himself. I know it was the best thing for me at that time.