Folke Filbyter is according the legends the grandpa to the Bjälbo-dynasty (Bjälboätten) (11th century). He was a never accepted among his sons and this statue is depicting him searching for his beloved son's son (which he never found). The name "Filbyter" might have come from that he castrated horses with his teeth.
See:
www.sollidensbil.se/sol_sv.kungar5.htm
Folke Filbyter