In chapter 17 of Good Night, Mr. Tom, William is discovered in the most traumatic circumstances at his family home in Deptford. He has been imprisoned in a closet under the stairs with his baby sister, who is now dead. He is covered in sores and lying in his own urine and excrement. He is promptly taken to hospital, and Tom accompanies him there in the ambulance.
At the hospital, everyone wants to know the nature of Tom's relationship with William. When he says that he is not a blood relative, they are reluctant to let him see William and adamant that he will not be able to take the boy away with him, whatever William's wishes are.
It is Mr. Stelton, from the children's home, who makes the final decision that William should go there rather than living with Tom. Mr. Stelton is not very clear in articulating his decision and seems offhand in making such an important choice for William. This makes matters even more frustrating for Tom. William's own mother has treated him in a viciously abusive manner, but Tom, who has developed a genuine bond with the boy and understands him better than anyone, is denied the opportunity to care for him because the two are not related.