In my book, that was exactly the sort of incident the law is for!
The misdemeanour decision looks like the police protecting their own.
I imagine there will be an out-of-court settlement by the police, which will provide a fund for the victim.
But in terms of punishing the malefactor, a civil lawsuit is likely pointless at best. A defendant needs to have deep enough pockets for there to be a proper target. Which is unlikely.
I don't doubt the family will seek a settlement from the police department; but that ultimately ends up with costs the public bears (insurers charge high insurance rates in a litigious society), which doesn't punish the right people.
So it sounds like the price of the incident to the perpetrator is loss of job and public ignominy. That is a hefty price, but not enough where a minor child is the victim, in my view.