>Fascism (/ˈfæʃɪzəm/) is a form of radical, right-wing, authoritarian ultranationalism, characterized by dictatorial power, forcible suppression of opposition and strong regimentation of society and of the economy.
There's plenty of parallels that could be made to support the assertion that Trumps base leans Fascist. Even the Trump slogan, "Make America Great Again", is a tenant of fascist politics. Alluding to a mythic past. This same sort of messaging is found around the world where fascism has made a foothold.
You are correct that authoritarianism is part of the equation.
Edit: "How Fascism Works" by Jason Stanley. While this book is wordy, it does a good job of explaining fascism and how it relates to the MAGA movement.
"And she, my family, and our friends are not fascists but they often support fascist ideals without know it." - there, that's it. EVERY leftist goes through this at some point.
One of the first things you could do is educate them on the origins of fascism. I mean this in a non confrontational sense. The unlearning process can be a painful one though so many people will disengage. It's tricky, all you can do is supply the information. Through learning the origins of what fascism is, they may grasp how it never went away and how it still effects us, daily. You could start with the following quote:
"Fascism should more properly be called corporatism because it is the merger of state and corporate power." - Giovanni Gentile
Few more useful links below:
How fascism works
The new faces of fascism
https://www.youtube.com/watch?v=b8AcmzqFdPM&t=11s - on Nazism
https://www.youtube.com/watch?v=hUFvG4RpwJI&t=1108s - again on Nazism
https://www.youtube.com/watch?v=q5ClScOsE-4&t=78s - on fascism & socialism
https://www.youtube.com/watch?v=Y1O3DWDzyv8&t=7s - capitalism & fascism
https://www.youtube.com/watch?v=u_rto6JPYQ8 - neoliberalism & fascism
https://www.youtube.com/watch?v=d6Nb3wbpljo - fascism & the political compass
It is not uncommon for a fascist dictator to obtain power this way. The book How Facism Works: the Politics of Us and Them by Jason Stanley describes how this process works and gives examples from history.
How Facism Works: the Politics of Us and Them by Jason Stanley .
Currently reading this book and find it describes current Republican behavior to a T.
Its a style of politics were people are fooled into blaming scapegoat groups (usually immigrants, minority religions, races, sexualities, marxists, communists) for their economic problems that tends to follow fiancial crisis when people are wanting change.
People are promised a return to some imaginary glory days.
Its a fake revolution that protects the status quo.