I'm going to yell at my friend for being late every day
Why would you yell at your friend for being late every day? Does his being late effect you?
He's really stubborn and he insists on not letting me drive him to work.
While I agree that it's good to be on time, it's really not your place to yell at your friend for being late. If his lateness doesn't effect you in anyway let him suffer the consequences without you scolding him.
It does affect me when he's late because he's my employee and I'm his boss.
That does suck if he is being late on purpose. You should fire him if he refuses your help. There's no excuse for him.