Doesn't really matter if he's Christian because Supreme Court appointments of the Catholic lady and the frat-bro probable-rapist who both are anti-choice. Charter-school lady with a war criminal brother as secretary of education because more charter-schools means more room for religious state-funded education.

Losing abortion doesn't effect the rich, and the rich want charter schools, so evangelicals get those two big things handed to them.

The holding a bible upside down thing is a token that evangelicals only take seriously in order to be able to have any claim of him being personally godly instead of acknowledging the cynical reality of voting for the guy who has multiple divorce, since marriage for him is a tool to have short term company of a trophy wife before they're replaced. Pointing at Trump holding a bible once is how they resolve this internal conflict.

Republicans throw more culture war bones to evangelism, which is also how you end up with the current anti-trans panic coming from not-very-religious people.