What happens when you assault a police officer?

My brother in all his infinite wisdom decided it would be funny to pester the local bike police who were minding there own outside a local bar on the beach. He was rather intoxicated and decided to poke fun at their vehicle or rather, lack there of. The police played along at first, taking it as an intoxicated joke, all in good fun, yet my brother continued. I don't know what was said, or who said what first, but my brother, again in all his wisdom decided to give an officer a little push. This push led to a bigger push and then my brother being subdued. What kind of trouble is my brother looking at if the officer decides bring charges against my brother?