My friend recently told me that under no circumstances should he be rescuitated. I don't know how to feel.

He said that under no circumstances should CPR be preformed or an AED used. I am a registered nurse and I work in the ER. I don't agree and told him that in the moment I don't know that I would be able to honor his request. I told him that I wasn't 100% comfortable with his request and I also told him that if something happened to him I wouldn't feel comfortable with letting him die since it is my job tto save peoples lifes. He stills says that under no circumstances should he be revivied. Can anyone help me either understand where he is coming from or how I can help him understand that I can't honor his request?

He might not want to be in a vegetative state the rest of his life. At least you know what he would want if that situation should ever arise.
Try finding out why he said that to you, hope he isn't "planning something".

You should be professional enough to accede to his wishes in this matter. If you still have doubts, he can have a DNR (do not resuscitate) tag placed in his file.