Unless there are circumstances that never came to light, or someone is telling one whopper of a story, good luck getting that to stick.
What is sh!tty is that they are more than likely charging that so that he can plea down to something else and they'll get their "conviction". I despise that aspect of the law - charge him accordingly and let the system do its job.
** just wanted to add - if you get in a fist fight in the state of WA, you should expect that you will be a felon and charged with 2nd degree assault. "substantial bodily harm" would seem to cover a black eye, busted nose, bloody lip, scraped knuckles/ elbows - you know, all stuff you recover from in a week but would expect to happen during fisticuffs.
" "Substantial bodily harm" means bodily injury which involves a temporary but substantial disfigurement, or which causes a temporary but substantial loss or impairment of the function of any bodily part or organ, or which causes a fracture of any bodily part;"