K.O.
My sister-in-law is a seventh day adventist and while I don't agree with some of their beliefs such as not buying anything on the sabbath and not eating certain things, she is a great person. I suppose in ways it is like baptist but in other ways it isn't. Maybe your son could ask his girlfriend what her family belives in as far as the religion goes if he is comfortable with that. Mean while, I'll be praying that God puts your mind at ease about the situation.
God Bless, K.