Bud blast sometimes happens just from transporting an orchid from one location to another. That coupled with the fact that the moss is staying very wet is probably the reason the buds have blasted. If your boyfriend's mom is growing and blooming phals in the same location and they are doing fine, then I feel pretty sure that it was the change in environment that caused the problem.
Can one repot while in bud and bloom? YES. Just be sure that when you do, you do not disturb the roots very much. Otherwise you will see more bud drop.