Asking Cop for Help Results in Drunk in Public

My question involves criminal law for the state of: California

My roommate was drunk and exiting the gates of a local fair when he stumbled down a hill. As he was getting up a stranger kicked him in the face. He saw a cop in Taco Bell and asked for help. Cop told him to go home. As he is crossing the street, the stranger tries to fight him. Another officer drives by so he hits the window of the officer's car to ask this one for help. Meanwhile, the Taco Bell officer comes running out and tackles my roommate and pins him to the ground. Of course my roommate is drunk so he is using foul language and getting a little belligerent while explaining that he just wanted help to not get in a fight with this random dude. Instead of helping him, the officers arrest him for drunk in public. Does he stand a chance in fighting the case?

was he drunk in public?

what anybody else was doing is irrelevant to that situation.

I suspect he is guilty of public intoxication. However, he can also be a victim of a crime. I suppose if the subject that had attacked him was present the police might have been happy to have arrested both of them. As it is, being intoxicated and engaged in a fight is usually sufficient to justify an arrest.

For future reference, tell your buddy that pounding on a moving police car's window is the wrong way to ask for help.

It usually results in being tackled to the ground with the occasional tasering.