OOH cardiac arrest

Theoretical scenario. Say you were out walking in the woods with a fellow medic, and someone nearby collapsed. You run over and find them in cardiac arrest so start CPR and call for an ambulance. Then the family who is with the person say to stop, that they have DNACPR and palliative patient. Would you stop? Would you ask them to show evidence and would you stop if they showed it? Or would you continue?