There are quite a few tear-jerkers. The one that got me was right at the beginning in case 2:

We stayed with the [recipient family] that night. In the middle of the night, Carter came in and asked to sleep with my husband and me. He cuddled up between us exactly like Jerry did, and we began to cry. Carter told us not to cry because Jerry said everything was okay. My husband and I, our parents, and those who really knew Jerry have no doubt. Our son’s heart contains much of our son and beats in Carter’s chest. On some level, our son is still alive