No and no; 4e makes it relatively difficult to kill PCs via HP damage. The 'dying' threshold is from 0 to their negative bloodied value, or half of their maximum HP. Depending on Odivallus's Con score he should be able to go to.. I'd guess probably around -15? 'Bleeding to death' doesn't work the same way, either; instead of losing further HP, you begin making death saves- if you fail 3 of those before succeeding one or receiving treatment, you die. Generally this means character deaths either happen in multiples or they don't happen, because it's pretty easy to save a dying character.. so either monsters are being especially brutal and deliberately executing downed characters with further focus fire, everybody who could heal the downed characters also is down, or the downed people get picked up in routine post-battle care. Odivallus will fall in that third category- he's down, but has not even begun rolling those death saves, and there aren't any other monsters around to prevent the rest of his party from helping him.

(Exception to above: Characters who go down in the area of a continuing damage effect/monster's aura/other thing that contributes damage without requiring any particular focus or action. Those can eat downed characters quite efficiently.)

As for raising dead, being able to do it on a combat-relevant timeframe (ie, 1 standard action) is a very high-level thing. But out of combat ressing is fairly available; it's a relatively low-level and inexpensive ritual, IIRC. None of the party probably know how to do it (especially because Odivallus is the one most likely to have the requisite feat to do Rituals in the first place), but they could pretty readily afford to hire somebody else to do it.