The server is ZeroPing.
You can play reg at 400 ping, you can play zp at 400 ping, you can play 400 ping on newnet/IG+/LC. Just because you can't do it doesn't mean someone who's probably played with that ping for decades can't.
The reason he won't use combos that often is because of the huge delay from the shock balls spawning, then you have another massive delay for the instagib shot to hit the combo, so he can't do combos at close range because it's near impossible to do one, unless someone else shoots his shockball.
Only thing I don't like about high ping players is, is how awful change of directions is when they are moving, they always seem to skip/teleport even if they aren't having connection problems, that's why I tend to avoid them in matches and go around them if possible.