My brother is finally starting with inferno, however he keeps getting stuck at the very start: the skeleton king. He uses a blizzard/hydra build (as in the pinned guide), and tries to kite him. However each time the king teleports he gets damaged too much & his hydra is spending almost all the time on the spawns.
So how you beat this unavoidable damage with a kite build?
Um, yeah, sounds like he is completely glass. It is better to avoid getting hit, obviously, but that attack is not serious - if it is serious for him, he's in for a rough ride against everything else in a1 too.
As far as what the hydra is targeting, he can re-cast it on top of the skeleton king whenever he moves around, but really the fight isn't a sprint, it is a marathon. There's no enrage timer and no real reason to try to kill him quickly. Just target him with your signature spell whenever you have the opportunity, and keep the hydras near him and blizzard on the skeletons.
Poop out duplicates as much as you can (illusionist procs or whatever) to eat the arrows from the archer skeletons.
Trying to keep him put is a good strat, same as with Rakanoth. I didn't actually do that; I Blizz/Hydra'd the spawn packs while Blizz/sig-spelling the SK (with Cold Blooded) and spamming duplicates to distract archers.
It might not have been the uber optimal/quick strat, but there were always lots of health globes lying around from the dead spawns to keep me from getting too nervous about my situation.
Oh, and Force Armor/Galvanizing Ward/Illusionist.
MR is correct in that it's more of a battle of attrition.