To answer the posts so far…
The retired priest is an old friend of the groom’s family, and was invited by the families.
They have not formally defected from the CC. They just stopped going to church. I’m pretty certain that they consumated their relatiionship prior to the wedding, for example. However, let’s be realistic and recognize that most Catholics (even divided to fallen away and not fallen away) have sex before marriage.
I doubt that they received a dispensation to have the wedding outside of a church.
I dunno if the priest had any sort of “permission” from the diocese he’s retired to, or the diocese in which the ceremony was held.
If this is an invalid Catholic marriage, what can happen to make it valid?