Ron Jr. has been a Prog since before they switched from "Liberal" to "Progressive". I doubt that he supported, let alone understood his father. It doesn't surprise me that the Trump of Ron Jr.'s fantasies is pretty much the diametric opposite of reality.
In the real world, Reagan supplied Stinger missiles to the Afghans, helping them drive out the Soviet invaders. In that same real world four and a half decades later, Trump transferred to Ukraine the technology to build Patriot missiles and has been helping Ukraine with intelligence.