I think he'll get a settlement, but not a massive one. He did initiate the contact, after all. Not to say he remotely deserved what happened to him, but if NOT confronting the other guy(s) is ever an option, then tort liability is lessened (as opposed to a situation, say, where a cop chases down and beats a protestor who is making no aggressive moves). You have a legal obligation to not initiate a confrontation if you can avoid it.
Again, I'm just saying what I think the outcome will be from a legal standpoint. Those cops were dicks, but it seems (despite immediate appearances) that the other cops did what they were trained to do--and to a certain extent at least, the two cops who shoved the guy did what they were trained to do afterward as well.
The real outrage is that phalanxes of cops with weapons and armor are marching on peaceful protestors--using the Trump pretext that maybe possibly sorta kinda some of them may get violent.