child custody mother not letting father see son

You do not ask a question.  Case law indicates that if consent is granted orally, it may be relied upon, and the passage of five years would indicate that you did consent.  However, every child custody arrangement can be revisited upon "changed circumstances," and the facts you describe certainly qualify as changes since the original order.  I suggest starting with the information, explanation, and linked resources posted at: http://willicklawgroup.com/child-custody-and-visitation/ Then schedule a consultation with this office or another family law specialist office, and you should know what you might do, and the reasonable costs, risks, and benefits of each course of action.