How terribly sad that mother let some small-minded idiot do her thinking for her, and what a shame she did not do what mothers are supposed to do and put her child first. If any man told me not to go to my daughter's wedding, I'd kick him out the door so hard they'd arrest him for speeding in Spokane.
To the OP:
Wow, thank you so much. I would be honored to have you as a friend and please be prepared to support you friend when the jerk leaves the scene. This will go down as one of the great regrets in your friends life.
Wow! OP, you really did handle this with grace. It's to bad that your friend has let a jerk of a man come between her and her daughter. Very sad. I think you handled it perfectly.