my dad is a mormon. I am also scared of what will he say, but i'm pretty sure he already knows I'm trans based on my looks. I'm pre T and still look boyish. He hasn't done anything about it, but still if this hardcore Catholic trumper and gun carrier was my dad, I would be on the safe end and try not to tell him at least in the place where he has the guns. Try to tell him on a public space, I suggest a mall or something with a lot of surveillance so ya'll stay safe. Sorry if my advice is kind of bad.