Trying to live with my son being a satanist

My is gonna be 19 in a few months. We weren't on talking terms because when my ex brought the kids down (he has full custody) my son has a shirt that said Satan loves me. Honestly Christmas went horrible. I said things. Made my son cry and go back home. I went to talk to my pastor and he said some things are more important than religion and I have to decide if the relationship with my son is one of those things. And it is. We have made up. He dresses really goth now and paints his nails black. He has satanic friends. I'm trying to accept it. Even tried to understand it. He gave me the satanic bible and I did read it to try to understand him. After reading I did see that what I thought it was isn't actually what it is. I'm still not a fan but I am trying. I really am.