John is right. When I used to drive a van, if I slammed on the brakes things would come flying forward and hit me if the rear section was a mess. If you let God in, He's going to start dealing with your messes. That means change, and change isn't always easy or fun. You'll slam the brakes on things you used to do, and things might start flying.
It's like the Israelites making bricks in Egypt. Pharaoh made them get their own straw after Moses showed up. But eventually Moses brought deliverance and freedom. Simply put, things often get worse before they get better, but there is no alternative to the process if you want things to get better.
I would suggest your friend read Hebrews, which is a great exhortation. 10.35-39 has:
Therefore do not throw away your confidence, which has a great reward.
For you have need of endurance, so that when you have done the will of God you may receive what is promised.
For, ​​​​​​​​​​​​​​​​​​​​​​​​​“Yet a little while, ​​​​​​​and the coming one will come and will not delay; ​​​
​​​​​​​​but my righteous one shall live by faith, ​​​​​​​and if he shrinks back, ​​​​​​​my soul has no pleasure in him.” ​​​
But we are not of those who shrink back and are destroyed, but of those who have faith and preserve their souls.
And the entire chapter 12 is
must reading about the discipline of God, how it's harsh for a season, but well worth it.