The thing is, he's already rejected things like Jin Roh, which is anime, yes, but for the stylistic things that usually identify anime (and that Josh hates), it might as well not be. It could be characterized as simply adult-rated animation, and it covers themes that Josh would probably enjoy.
But he rejected it out of hand.
So I don't think he'll accept anything if it's recommended under the umbrella of anime, because he doesn't know, and has no reason to know, that it's not the usual bullshit. Won't matter if you tell him, he won't take it.
That being said, Rurouni Kenshin. One of the few I will actually watch, even if it is dated.
Aside of the anime cliches that the changes and filler add to the anime (the show, that is), which he'd totally hate, he'd hear about the author's pedo incident and he'd tell you to fuck off.
That said, the Trust and Betrayal OVA is a masterpiece of not just anime, but animated cinema and everyone should watch it. Hell, it's one of the best (semi) historical samurai movies ever made.
And the soundtrack is FUCKING AMAZING.
(I say "movie", but it's a 4-episode miniseries; there's a director's cut that turns it into a movie, but somehow the director fucked up and made some bad decisions, particularly with the music, that make it worse than the episodic version)