I say that if you allow a difference in belief systems to prevent you from celebrating the personal accomplishment of a close friend you let the "borg" win. Standing in front of 100 people to give a 5 minute reading is an accomplishment when your 30, even more so when you're 7. So celebrate with him.
I've had enough of letting ideas about the meaning of things affect reality- my relationships with others.
Just my two cents.....