FITCHBURG — A Boston nonprofit that assists abuse victims involved with the state Department of Children and Families has started a fund to pay for the burial of a horrifically beaten 6-year-old girl, whose parents are charged in connection with her death.Police found Sophia Brito badly bruised and unresponsive April 10 in the family’s Stoneybrook Road home in Fitchburg with her seriously injured 9-year-old brother, Julian.