Kenny still kills him, but if you perform CPR on him fast enough (only a rumor, I don't know if it's true or not), Larry will gasp right before he gets the salt lick dropped on him. People are all arguing that Kenny is a Feminine Hygene Product for doing that and saying it's murder and blah blah blah. Personally, I killed the jerk, because I really thought he was gonna turn. Plus, he would've tried to kill Lee the first chance he got, so why should I give him that chance? Plus he probably wouldn't have even thanked you if you did succeed in saving him. He'd probably say: "Damn it, why didn't you revive me faster! My daughter could've done a better job saving me from my self-induced heart attack! RAWR!"
I agree with Kenny, one way or another it had to be done.