Oh my god! Okay first of all find out if there's a church page on socmed (your church) if yes go thru the followings and followers and maybe you can find him there, send a req coz "oh your account was in my recommendation and i recognised you from church..." And if the church doesn't have an account then the next time you see him have your sibling/close friend (one you can trust with your life) approach them in a friendly way... Like to help him or something and then they can introduce you to him. And if nothing from the above can happen then maybe make an "accidental" eye contact with him, a small smile or a wave, a simple hello which can be a start of a friendship. Do keep me updated 😚