The woman was pregnant, but she was definitely not this boy's "stepmother," nor was that bunch of folks sharing a house with him his "family."
Are you saying that the boy’s father wasn’t married officially to the woman pregnant with his child? That is no excuse for this 11yo’s crime. There are plenty of couples living together with their children from other marriages, and even though they may be wrong to live together without marriage, that does not explain an 11yo boy committing this crime.