You may consider her boyfriend a moron, and he may well be a moron. But she might not think that way, so you should probably be respectful of him around her.
(A mistake I made. I called her boyfriend a midget because he was short. That isn't what I wanted to say--I wanted to call him something much more accurate and ruder. To this day I still have no idea how those two worked together. As I figured, he dumped her within a few months. His loss, of course. But even though I was right, I can't imagine how bad of an impression that must have made on *her*)