Is a NDA binding between father and son if this was only agreed verbally?

Is a NDA binding between father and son if this was only agreed verbally; and in a general sense covering all business matters while the business is being developed? I understood verbal contracts to be limited to a single day. However, there was a past relationship, father and son, including previously founding companies under strict verbal NDA agreement. My invention was disclosed in email, including intent to patent, and the other party stole and licensed this commercially. No patent was filed; given breach of NDA provisions. Our family relation is since estranged.