He needs to get over that shit.
First, in an existential fight for the Republic, you suit up and fight with everything you've got for the team that is fighting FOR the Republic instead of fighting tooth and nail to destroy it to fragmented rubble.
Second, take a deep breath and accept that many/most/damned near all of those "conservative" values and ideals you once believed in have either been PROVEN to be shit (e.g., "trickle-down" economics) or were just lies (party of "equality" my ass -- it's a fucking nakedly racist and xenophobic party).
Third, realize that things conservatives love to rant about as leftist socialism are actually middle-of-the-road policies that exist in other healthy developed countries, and that we are actually better equipped to execute than most anyone.
Fourth, add all those things together, and you realize that what y'all call "center-left" in America is actually center, even center-right everywhere else that has any sanity remaining. So, fucking join the team, and fight for a better future for this Republic, starting with step 1: saving it from the psychotic fascists who are the GQP.