Should I tell my friend he needs to grow up?
Maybe. Why does he act like a kid?
I just think he should be more mature
It is normal to want adults to take responsibility and act mature. You might want to speak to them and tell them how you feel if you think they are harming themselves.
I have told him to grow up and he said 'okay mom' and I'm really mad right now.
I get it, but you got to remember we can't control how other people behave. We can offer guidance, but we can't make others do what we want them to.