Giving one children’s good advice is always a a parents reasonability.;
No matter how old they are.
My advise is be responsible and enjoy your life.
I don’t have to tell him to be a good person. Why? Because he is. Fortunately we have a bond. So he can come to me. I don’t need to nag him. I raised him right. And I was blessed. He learns from not just his mistakes. But even more from others.
I’m sorry if you don’t have confidence in your adult children. But, he’s a man now and I refuse to nag any man. Perhaps step back and see if your parenting skills worked in your adult kids.