wait, so the Father and the 18yr old Daughter were at the Playground drinking Beer

Ding ding...
We have a winner
Also, the daughter was "combative". Strange word in this circumstance.
Something tells me, theres more to this
the father was probably wasted (maybe daughter too) and the gang saw this, easy set up
Maybe they mouthed off first? I mean, it's shitty shit yes, but why put your daughter in that situation.