I'm not going to invite my friend to a party that conflicts with his religion
Why don't you want to invite your friend?
I would rather not invite this person since they would never participate in the party anyway.
Well, the choice to attend is entirely up to them. You should refrain from getting involved with other people's religious beliefs. You may not have full understanding of their religion.
I want him to ditch his religious beliefs and enjoy the party.
Wanting him to cheat at his religion is a pretty selfish stand point for yourself. It is more fair to allow him to choose whether or not he wants to attend the party, and to try and keep his religion out of it. Simply allow him to make whichever decision he feels is best for himself.