As you have indicated it is dominance related. The bitch has always seemed more dominant but the male ( a slow to mature breed and a neutered male - this can lengthen the emotional maturation of the dog) is coming into his own. He now sees himself as the Alpha and is pressing home his point in no uncertain manner.

I would suggest to your friend that she shifts the way she treats the dogs so that the male is now treated as the higher ranking dog. Once he sees his role as supported and the bitch sees that he has the leader's support things should settle down in a couple to three weeks.
Suggest that she feeds the male first, greets him first and gets the dogs to sit at doors and allow the male through first, after she has gone through, of course.

Hope this help - tell her not to be embarrassed it really isn't uncommon. It would probably stop anyway as the male matures further and feels safer in his new position.