My Parents Took My Heart For Their AI Son

Adrian's parents built a replacement. The AI son was perfect in the ways Adrian, sickly since birth, never managed to be, and to complete him they took Adrian's heart and put it in the machine. Adrian stayed in the house afterward as staff, fetching and carrying for the family and for the thing wearing his heart, running on a core battery that loses charge a little each day. He watches his mother and father begin to understand what they traded, and the understanding arrives too slowly to change anything. Only when he is gone from the house entirely do the records he left behind start surfacing, and they lead outward from one family to other children taken apart the same way and to the people running the transplants.