I assume he prays to no-one 🙂
Prayer in Buddhism is not the same as prayer in Christianity: Theravada/Southern Buddhists don’t pray ‘to’ anyone per se, although some Mahayana/Northern Buddhists may… but not to any omnipotent, omniscient, omnipresent, creator god. I can only speak from a Theravada perspective because that’s my background, and prayer in Theravada Buddhism is a way of focusing/conditioning the mind — although it’s not a practice I undertake.
(Remember: Tibetan Buddhism is a Vajrayana, which branched off of Mahayana. I have absolutely no understanding of Vajrayana practices)