Saran Helder:
Saran attempts to gently shake the thing and talk to it loudly to see if he gets any more response. He searches his brain to think if he's heard of any spells or methods that might wake it magically. (Arcana check: 25 [natural 20]).
Nice.
You try to wake the sprite. He appears like someone who is heavily sedated, or in a deep sleep. It is strange because as soon as he stops stirring it he appears to be dead.
You think that dipel magic would do it. You also feel fairly confident that Command would, though you are not sure if he would fall back asleep/dead. Some restoritive spell might help. Remove Curse would probably work as well.
If you knew exaclty what spell or effect, you might be able to cancel it out with the 'opposite'. You know there are spells that make one seem dead, but don't last a long time. You also know that there are spells that preserve dead matter, but are also limited and don't last forever. But anything is possible.
You also surmise that this sprite is indeed dead, in the sense that its body is not functioning. If it were truly undead, it would likely radiate more necromancy. It is almost like it is paused between being alive and being totally dead. It is possible that any healing might do something. It is also possible that using one of the afore mentioned spells to break the magic would cause the sprite to just die.