Spencer's father adopted you when Spencer was a baby. you were raised together like siblings. it's not like Spencer's mother would remember she only had one kid. when things got too difficult, William left and abandoned Spencer and you in the care of your schizophrenic mother. Spencer tried is absolute best to take care of everybody once his father left. even though he was 10 years old, he had the intelligence of an adult and he knew how to do things even if he couldn't physically do them.