Hmm, I guess it really depends on whether the value you die at (-con) is considered a statistic. I don't believe it is so I would say RAW no.
Maybe this is a hardline approach, but if a temporary Constitution bonus gives you real hit points that can keep you alive, then I would say that temporary Constitution damage takes away real hit points and can kill you. Otherwise, what is the point of an expensive poison that inflicts Constitution damage?
Damage to your Constitution score causes you to take penalties on your Fortitude saving throws. In addition, multiply your total Hit Dice by the Ability Damage penalty and subtract that amount from your current and total hit points. Lost hit points are restored when the damage to your Constitution is healed. See Ability Score Damage below.
It does remove HP, the question is does it raise how low you have to go before you die?
Expanding upon what I said above:
Ability damage doesn't actually lower the score... you don't lose access to feats or spellcasting if their pre-requisite stats take damage. I'm inclined to say because it isn't mentioned, is not a statistic in the game sense, and the ability damage doesn't actually lower a score (only applies a penalty), unlike drain, that you would die at your actual constitution value.
EDIT: tl;dr: You'd die at -12 imo.
Some stats require other stats to be recalculzted when they Raised or lowered. To remove the.need to recalculzted these they other stats every time your hooded they made a seperate rule for temp stats.
So by the rules I think if you hit the heavily armored fighter with an 11 pt str drain from ray of enfeeblement he suddenly with his 9 str doesn't struggle to stand in his 220 lb load.
Here's the thing.. its likely one of the most ignored rules in the game. Many of the stat recalculations can be ignored until they matter.
I would ask your dm if he wants to use the temp stat ruled in the book. If that is the case your char lived. If he doesn't clarify that just so its clear.
Aioran, yes that is what I am asking. In the game today, my Wizard would normally have a Con of 12 but due to Cloudkill, the stat was lowered to a 6. Would it be a death at -6 or at -12 HPs?
The stat was not lowered to 6. Ability damage does not change your stats at all, it just gives penalties. So with a Constitution of 12, if you take 6 Con damage, you still have a Constitution of 12. Your score does not change, and so you still die at -12.
Ability drain, however, does reduce the score in question. If you Con 12 character had taken 6 points of constitution drain, he would have a Constitution score or 6, and so die at -6.
Read the first paragraph under ability damage in the glossary. The stat is not actually reduced, you just take penalties associated with it. So when it says you can go to negative con before dying, it means full stat.