Daniel being a few thousand years old and able to revive makes the entire series make so much more sense. He doesn't tell Jack because while Jack would be personally relieved that he isn't going to get Daniel killed, he'd be annoyed that Daniel's not fighting more and he would also think of Charlie and that wound does not need re-opening. He does not tell Sam because her scientist's mind would not let it pass without experimenting. He doesn't tell Teal'c because he's pretty sure Teal'c knows. It's far too late to tell Cam Mitchell and Vala would just misuse the information despite her affection for him.