Can I yell at my best friend for being in a bad relationship?
That seems excessive. Why make your friend feel bad on purpose?
I didn't mean that, I mean to say it's not his fault that the relationship is not the ideal relationship
Yelling at him seems excessive. If he's in a bad relationship why not support them instead? I'm sure they'd appreciate that over being made to feel bad for their choices.
I know but my best friend should have always listen to me.
Sometimes being a good friend means letting other friends make mistakes as long as there is no immediate danger. Just be there for your friend when they need you and try to help in any way you can.