The Boy From The Basement by Susan Shaw

For Charlie, the basement is home. He's being punished. He doesn't mean to leave--Father wouldn't allow it--but when Charlie is accidentally thrust outside, he awakens to the alien surroundings of a world to which he's never been exposed. Though haunted by fear of the basement and his father's rage, Charlie embarks on a journey toward healing and blossoms when he becomes an unconditionally loved and loving member of the right foster family.