If Jesus said "render unto Caesar what belongs to Caesar" and Paul had Timothy circumcised (with the intent of sharing the message of Christ's resurrection with Jews), I believe it's in the best interest of Christians to abide by US marriage laws. Demanding others recognize our own rights is usually a bright red flag that we need to adjust our perspective and priorities and check our motives.
But that's my opinion and not the most pressing issue in the immediate situation (though it's always important to pursue a sound understanding of the breadth of Scripture). I'll be praying that God sends someone in to your father's life to guide him toward a stable and wise course and, more importantly, to dependence on Christ. Sometimes children are granted the opportunity to deliver a word of correction to a parent, but it's the exception and not the rule. Even if the opportunity arises, the situation is awkward at best and could turn hostile at worst. I'll be praying that the Lord would task another Christian with that call--for your sake--but ground yourself in Scripture and be prepared to speak corrective truth in love to your father should the need and prompting arise. I'll also continue praying for you in all this.
But that's my opinion and not the most pressing issue in the immediate situation (though it's always important to pursue a sound understanding of the breadth of Scripture). I'll be praying that God sends someone in to your father's life to guide him toward a stable and wise course and, more importantly, to dependence on Christ. Sometimes children are granted the opportunity to deliver a word of correction to a parent, but it's the exception and not the rule. Even if the opportunity arises, the situation is awkward at best and could turn hostile at worst. I'll be praying that the Lord would task another Christian with that call--for your sake--but ground yourself in Scripture and be prepared to speak corrective truth in love to your father should the need and prompting arise. I'll also continue praying for you in all this.