Good luck with explaining that to my Catholic father and Presbyterian mother.
my uncle is a catholic priest..
sometimes, an individual priest will bend the rules, but for the most part it is not allowed...
there are immediate members of the family that he could not perform the wedding for because he basically is not allowed..
he still came to the weddings, just could not partake in any official way
But I bet your Presbyterian mother was baptized and is a Christian. This was about a non-Christian.