We don't know the facts. The police get called out on using unnecessary force a lot, and sometimes they do, but it's not as simple as "BUT HE HAD OFFSPRING WHO HAD OFFSPRING, AND THUS HAS SOME SORT OF CRAZY AUTOMATIC POLICE BRUTALITY CLAUSE IF EVER APPREHENDED FOR ANYTHING!"
Now, see, we don't know what's happened. If he complied with them and got smashed into the floor? Yes, that's unnecessary force. If he actually resisted? No, he got tackled because he was stupid.
It looks bad, I know, it automatically makes you side with the underdog when there's three police on a bleeding old man. But guess what? The point of the police isn't to give anybody a fair fight. The point of the police is to make sure there's going to be minimal injury. It's so very easy to holler "POLICE BRUTALITY!" when things look one-sided and somebody's bleeding, but guess what? If they didn't act fast and decisively in these situations, it might look even uglier, maybe with someone clutching their guts with a knife in the belly. Somebody resists arrest, he's a potential danger to everyone around them. I'm not talking about this situation per se, I'm talking about the big picture. Just remember this: if you resist arrest, you're telling them you're a potential danger and have just agreed to being put in harm's way for the sake of protecting others, including the officers themselves.
Have you seen what can happen in five seconds if somebody's allowed to resist and actually starts really, veritably resisting and manages to pull some shit? The pictures aren't pretty. There's a reason the police utilize force, and the detained is put up against overwhelming odds. It's not about a fair fight, it's about trying to make sure there won't be a fight at all and things won't turn really damn ugly for everybody.
All I'm saying is, we don't know the facts. Eyewitness accounts, as stated, don't mean jack by themselves, without any kind of examiniation. There's no victim here before they can actually prove he wasn't, in fact, "flailing his arms around and resisting arrest", and we should reserve judgement. He might be the victim of unnecessary use of force, he might have gotten it for a reason. I certainly can't say and thus won't.