I know in Baldur's Gate 2, if a stat was lowered to 0 the character would die.

What happens in IWD2?

For example, let's say a Dwarf with a CHA of 1 puts on a suit of armor with a -2 to CHA. Does he die? Is is an item he can not equip? What's the deal here?

TIA

Dunno, but it should as in 3E Having a stat below 1 is instant death. I think the only way of knowing that is trying. Try creating a 3 str char and cast that spell that lower str by 1d6 and see what happen.

No, They don't die. I used a cha-decreasing armor on my half-orc barb/druid with a cha of 1 without noticing anything.

from the rulebooks at least it depends on what stat.

Constitution 0 = death.
Strength 0 = unable to move or do anything at all. pretty much unable to keep your eyelids open.
Dexterity 0 = unable to have any control whatsoever over your actions, pretty much like nerve poison where you cant control body.

Charisma and Wisdom are somewhat dependent on eachothers, and if you have 0 in one of them you shuld get 0 automaticallyin the other. (lacking presence and selfawareness)

Int, uhm, vegetable :p

I belive the game handles this by only reducing to 1, but 1 is usually very bad sideeffects anyways (save int and cha) If you get 0 strength you have like 5 or 0 pounds carying capasity, even a healing potion is to much for you. Dexterity at 1 and you get a huge penalty to armor class and to hit with missles etc.

My last game my bard got drained away all her strength in the last battle, so she was stuck in the middle of the fight without the posibility to strike back (uhm -10 to attack or something) and unable to move.