I can kind of see where she is coming from IF she and her son were as close as she says they were before the girlfriend came on the scene. I've seen guys greatly discontinue contact with relatives and friends (to the point of shutting off contact) because they are *so* in love and can't possibly have time for anyone else.

This may or may not be the case here, but it's a possibility.
However, I don't think it's appropriate to blab to the papers about it, and kudos to the couple for not responding (in public).