There is not enough information here to answer the question, but as a general matter, if there has never been a custody order, the parents of a child are presumed to have joint physical and legal custody until a court states otherwise. Some information and background is posted here, but your parents -- probably both of them -- might be well served by consulting with a qualified family law specialist before attempting any form of "self-help."
Answered on Jul 24th, 2018 at 10:10 AM