Can she be punished for keeping the child from his father?

My fiance's son's mom up and moved him to Florida from Maryland without telling him. They had joint physical custody of the child. She will not allow him to see the child and just recently she called to tell him he could see the son only if he drives to North Carolina and meet them there. He drove down there only to find she did not show up with the child. Are there laws in Florida that can punish her for uprooting the child when both parents have joint custody and can she be punished for keeping the child from his father? What sad is that he is a good father to his son and yet can't do his fatherly duties. She uproot the child because she was dating a member of a racist gang and the boyfriend attacked her. Her son is biracial, she is white and my fiancé is black.