I'm rather new to this website, so please hear me out.
"Irresistible grace" is a term which applies only to the pre-determined elect of God. Those predestined were chosen before God created the world and they are the apostles and prophets. They're also the "few" when Jesus said, "Many are called, but few are chosen."
"Irresistible grace" does not apply to the many who are called unto salvation. For them, they can resist the calling of the Holy Spirit, the witnessing of believers and the testimony of Scripture.
This doctrine is more like what your friend is talking about when he says he does not agree with your doctrine.
Since both doctrines are correct, you won't be able to convince your friend he's wrong and he won't be able to convince you to change either. This also explains why Calvinists and Arminian Methodists have disagreed over this doctrine for centuries. Neither understood they both were partially right.
