Question about daniel in the movie 'orphan" ***WARNING CONTAINS SPOILERS***?

I watched the film Orphan and im quite confused because when Esther suffocates daniel with a pillow then his heart raate goes down too 0 so you assume he is dead but then someone says they have a pulse on him and he's in cardiac arrest or something? ? ? then later when kate goes crazy and has to be tranqualised then she is in a hospital bed and she is asking about Daniel and the dad says he will be fine but then you don't see him again in the restt of the film and no one mentions him or anythiing soo i dont know if he die or not and im really confused