That's the beauty of this games, each player can have theyr own playstyle.
I like to test how much freedom there is in the game, one of the ways is trying to heal npcs to see if there are deads that can not be avoided because of how the story must evolve.
I think this is one of those (to consider the option of a player finding a way to heal and remain alive implies a lot of writing and programing to have different outcomes in the Goblin Camp). I think, also, Larian should calibrate better the scene: if you cut of the brain snacks the mindflier has under tehir control, either killing the three or making them go away, the mindflier instantly dies because they don't have any more life support. Or, if they want to maintain the chance to trig the dialogue and cutscene and the option to be killed because you kind heart character decides to help, they can make the mindflier as impossible to target with healing spells or potions (like they do with the resurrection scroll, that you can use only on your party members, or with the talk with deads spell) and let the chance to heal the mindflier to be only in the dialogues and cutscene.
[There's another dying character I tried invain to heal: the monk near the door of the underground passage, again I get its an obbliged death because his passing brings to the cutscene with the tadpole, but again it should be made clear that there's no way to cure him [something that breaks how healing, either with potions or spells or scrolls, functions: how is possible to heal your party even if they are at 1 HP, aid them if they fell unconscious, but not a monk still able to speak?]