Trump does not have “friends” in the sense that most people use the word. He is clearly not capable of seeing other people as human beings, they are just props that he sees only in terms of how they can benefit his scams and his ego. He has a mix of acquaintances of convenience, hangers-on, toadies, and people pretending to like him in order to advance their own agenda or status in some way. All of whom he would throw under the bus in a minute (unless they have incriminating evidence on him, or unless he sees them as someone powerful who may be a great help to him in some way.
Everything is transactional with him. He would never do something nice, or help anyone unless he gets something in return that he wants.