1 - if an investigator with one health left draw the curse of yig encounter card is he instantaneously killed?

2 - if an investigator draws two curse of yig cards they stack? (-2 health??)

Thanks

1: Yes, if you have Damage on you equal to your Health, you are defeated and suffer physical trauma, regardless of whether this came about because you took damage or your health was reduced.

However, it's important to note that you are not usually Killed if you take too much damage - you are out of the scenario and suffer trauma but you will live to fight another day. Killed and Driven Insane are terms that refer specifically to an investigator being permanently and irrevocably lost. An investigator is Killed when they have physical trauma equal to their health and Driven Insane when they have mental trauma equal to their sanity, although game effects or scenario resolutions can change this (in certain situations, if things go badly enough for you, you can just be straight-up Killed regardless of your trauma).

2: Yes, they'll stack, and you'll need to get rid of them separately.

Thanks ^^