Maxperson
Morkus from Orkus
Do they? In-game, I mean. The OP was rather unclear as to what was player knowledge and what was character knowledge. Also, even if the characters know that a restorative spell exists, do they know if that spell works on that particular condition?
The players are arguing that they should kill her character or let her die naturally, since they won't be able to restore her until they hit level nine and can cast greater restoration, and they won't be able to reach a settlement to hire an NPC caster for at least a few months in-game (probably eight to ten sessions).
From the OP, the players were arguing about things their PCs would be doing. waiting until level 9 or reaching an NPC caster. I suppose it could have all been OOC, but it doesn't seem that way to me.