First, I am sorry that you lost a friendship which was obviously important to you. I am a gay white Jewish male and unfortunately I have many relatives who embraced Trump—and who insist that everything he says is true (even when he blatantly contradicts himself).
I’ve come to the conclusion that Trumpism has become, for all practical purposes, a religion. He skillfully appealed to (primarily) white people who had a deep and abiding sense of grievance and resentment, nurtured over many years by rightwing media. They are “lost” and he is their “savior,” taking them back to the Garden of Eden—small town, white Protestant America where the “American dream” was a real possibility.
Attempting to reason with most of them is utterly futile, for the same reason that arguing with a fundamentalist Christian is almost always futile. They live in a universe constructed by faith and reasoning is an assault on their belief system. Their moral “facts” trump (pun intended) our objective facts every time.
I admire your continuing efforts to open up her eyes and her world. I wouldn’t have the patience myself.