Cheating is wrong, plain and simple. It doesn't matter if it's some random person on the other end of a computer or your own flesh and blood. The problem here isn't the OP. The real problem is that this "friend" has been putting the OP in an awkward spot by not changing his tune, especially after the OP spoke to him about it. Real friends and family don't put you in a compromising position if they can help it. The responsibility in a relationship rests on both parties; it's a two-way street.
Good on you, OP, for doing the right thing. I'd also suggest dumping this so-called friend. He has no integrity.
P.S. I can't believe how many of you openly admit to botting. This everyone's-doing-it-so-idgaf mentality is pathetic.