His mother, who worked at the orphanage, died when he was born and the fate of his father is unknown. According to Grelod the Kind, he has become something of a leader among the other children, possibly due to his lifelong residence at Honorhall.
Like the rest of the children at the Orphanage, Samuel has suffered under the cruelty of Grelod for some time. If the Dragonborn kills Grelod, he will celebrate, along with all of the other children.
If Hearthfire is installed, Samuel is one of the children who can be adopted. The Dragonborn will need to kill Grelod, since she refuses to allow the childrens' adoption, and they will also need to have built or purchased the appropriate furniture for their home.
Grelod "Those who shirk their duties will get an extra beating. Do I make myself clear?"
Samuel "Yes, Grelod."
Runa "Yes, Grelod."
Hroar "Yes, Grelod."
Francois "Yes, Grelod."
Grelod "And one more thing! I will hear no more talk of adoptions! None of you riff-raff is getting adopted. Nobody needs you, nobody wants you. That, my darlings, is why you're here. Why you'll always be here, until you come of age and get thrown into that wide, horrible world. Now, what do you all say?"
Samuel "We love you, Grelod. Thank you for your kindness."
Runa "We love you, Grelod. Thank you for your kindness."
Hroar "We love you, Grelod. Thank you for your kindness."
Francois "We love you, Grelod. Thank you for your kindness."
Grelod "That's better. Now scurry off, my little guttersnipes."