Either two or three. I know he got two out and he posted some art from a new artist he hired for issue three but I don't remember if it ever got finished. Though to be fair to Lewis, if I remember correctly the problem was the artists he was paying weren't working very fast (Unless he was only giving them one page at a time and not writing the script until they had finished the previous page which, knowing how he works, might have been how he did it) and eventually ghosted. I can empathize, the few times I tried to make a comic, the artist being slow as fuck or just disappearing was always a problem, and it's a recurring issue in comics outside of DC and Marvel.
See, with DC and Marvel, they wait until they're two or three issues ahead before they offer the first issue to retailers. And the artists are being paid enough to focus on the book, or if they start falling behind, the editor just hires a guest artist for an issue so they artist proper can skip that one and start work on the one after to make sure the deadlines aren't missed. As it was explained to me in creator-owned stuff, the book is solicited before the artist even starts drawing because that's when they get paid, not before, so most won't even start until they get their money, which is understandable because they need to make sure the bills are paid while they're working. But then they fall behind because the lack of editorial oversight means they can take their time on the issue. The better artists use this opportunity to fix errors they make or add more detail than they normally could at the big two. Most, unfortunately, just use it as an opportunity to slack off.
This is even worse in webcomics and self-publishing (I think Revolution was through a small publisher but it was almost the same as self-publishing) because there's even less chance of the book taking off, so the artists usually see the job as a waste of their time because they think it won't go anywhere. Even if they're getting paid, some artists lose interest because they're used to drawing on their own schedule when they're in the right mood, and then get pissy when you're asking them where the fuck the pages you paid for are. It's sad when Andrew Dobson working on the Brentalfloss comic is actually an example of a better work ethic than some people out there (His Samus commission is about the norm).
As for why Lewis doesn't just use his patreon money to make another comic, I think the fact that Lightbringer and RotM didn't immediately take off soured his mood on being a comic writer. So he'd rather just stick with what's worked for him in the past and not make any attempts to evolve.