How did he treat Reagan and Bush?
He blamed Bush for not treating him fairly during the campaign. He was bitter over it.
He spent the first six months to a year of Bush’s first term, going on every talking head show he could get booked on, differing with Bush on nearly every policy.
I’m not big fan of GW, but you don’t trash our POTUS early on, and even on policies that as a Conservative we agreed with. He did.
McCain was relentless. Of course the media ate it up.
As for Reagan, he spoke out against his policies too from time to time. It’s been so long now, I don’t remember specifically the things he disagree on.