One of my half-sisters is a one-issue voter: abortion. This is how I responded to a recent IM by her and her friends.
“You people are part of a cult — a t***p cult. You support a man who has sexually assaulted women — and bragged about it? He has no knowledge of history, which really should be a prerequisite for holding federal office, by his ignorance of the fact that Fredric Douglass died over a 120 years ago. He has denigrated the families of those who died in the service of our country. He called them suckers and losers. He is a danger to our democracy. You have been duped because he saw your hot button issue: abortion. You are willing to accept sedition and treason in order to prevent abortion. He condemned that act and gained your support, never mind what else he stood for. While I believe you are all intelligent people, you have been duped, and I grieve for your beliefs.“
kmkat & her kneedles 
Add to that his unsettling (to say the least) attitude towards his daughters. He’s made it clear a number of times that he lusts after Ivanka and in an interview speculated about the potential size of Tiffany’s breasts when she was still an infant. His friendship with Jeffrey Epstein must surely be disquieting for any decent person, yet – as you say – when he cynically adopted an anti-abortion stance to appeal to a section of the electorate, they evidently fell for it. I think it highly likely, given his lifestyle when younger, that he was involved with at least one abortion himself.
Do you think that his breathtaking about turn last week – from deliberately inciting the insurrection to afterwards condemning it – will finally bring his most demented followers to their senses about him, or will they be able to invent excuses for his betrayal?
It is mystifying to me . . . how so many folks have been blinded by their “one issue.” I just can’t wrap my head around it. (I blame . . . the fox news.) (And their ilk.)
He wants to control others in every way possible, without being held accountable for his own actions. That explains everything he has ever done.
I’m sorry that your family has to be pulled apart like this. It feels like fever.