Tell him whatever you have to keep him out of your hair, most cult members try to drag their spouses into it— and you’re not doing anybody any good by going along with it. Nor do you deserve to be hectored or shamed by ANY family members. Don’t put yourself through it.
Do the right thing in the voting booth and take the path of least resistance at home, hopefully someday he’ll snap out of it, or you’ll find someone better- although just about anything would seem like an improvement after an enduring an entire election cycle with one of these MAGA loons in the house…