Why doesn't he like anime? If he has specific reasons and doesn't seem interested in getting into anime/manga, then it's kind of pointless to try getting him to like it. And the more you push it on him, the more he's likely to resent it. Not saying you do that, of course, but just friendly advice.
On the other hand, if he hasn't found anything he likes and is interested in getting into it, plenty of folks here have some pretty good recommendations.
It depends what sort of things he likes in general.
Maybe something like Me and The Devil Blues. About blues musician Robert Johnson. Maybe Oyasumi PunPun. About a... Well... Find it, you'll see. Does he like cheesy hollywood action movies? Black Lagoon. Agriculture and college shenanigans? Silver Spoon. It depends what he's in to.
What does he like? It's never a matter of liking manga, it's a matter of what you like. For example I don't like sports stories. I won't read it in books, watch it or tv, or read it in manga. However I do like martial arts so I play Streetfighter, watch the Ip Man movies, and read kungfu mangas.
Horror/gross: Litchii Light Club or anything by Junji Ito Action/Kungfu: the original Dragonball or Fist of the North Star Comedy: One Punch Man or Saint Youngmen Sports: Slamdunk Alt-History: Ooku
If he likes superhero stuff I'd recommend the Tiger and Bunny anime.
Look at his other interests and try to pick something that resonates. Forget about shojo stuff or anything remotely soap opera-like. Most guys don't want to see a romance as the center of the story. But you know him better than a collection of weird strangers on the Internet. What books/comics/movies does he like?
Has he told you why he doesn't like anime or manga? Not everyone is going to like it, as much as you want them to. My friends try to get me into it once in a while too. It's not my thing and no amount of persuasion is going to change that. If he's never seen any before, it can't hurt to have him check it out, but don't push it if he just doesn't like it.
I don't think he doesn't like it, it's just nothing that has been shown to him he has had much interest in.... I don't think he has seen the right anime, his sister loves anime but would do things like watch a movie over and over to where everyone but her got tired of it so he found a disliking of it. I was hoping to try to let him experience different genres of anime.
That's what most of my friends say to me when I tell them I don't like it. But honestly, it's the style I don't care for more than anything. I've never been much of a fan of anime art/animation (except for a brief period when I was in high school and didn't mind some of the better art on here). The one anime I've ever enjoyed was Princess Mononoke, and I liked it in spite of the style. Then again, I've never really liked western comics or animation much either. I'm a book person, I guess.
If there are any particular aspects of anime he doesn't like, perhaps you can find one that doesn't include those things and he'll enjoy it more. I'd probably like anime a little more if all the female characters hadn't been either weak damsels or domineering sex-symbols in the anime my ex had me watch. I hate those stereotypes in any media, whether it be books, video games or films. They just seemed to be especially prevalent in the anime I've been exposed to.