How does Daniel die in orphan?

In orphan, Daniel is the son right? ok well, esther, the orphan, burns his treehouse while hes in it. ok? then he falls out of it. then he landed in the snow. while he was in the hospital, esther went in his room, and suffocated him under a pillow. while she did this, she had his face mask, which gave him oxygen, off. so he couldn't breathe. BUT he recovers. 3 dayys later