Subscriber = Free, those are people who simply get notified of when you upload.
You're right, it also has nothing to do with getting paid. You get paid for ads watched and clicked, so his paycheck is tied to his views more than his subscribers.
Also, note that even with a monetized channel, not all videos are eligible for monetization and some ads pay more than others. For instance, talking about CSA, domestic violence, etc. can risk that video being eligible for ads. Videos about JWs and cults also aren't going to pull in premium ads so even if they are monetized, they won't earn much.
He also needs to consider time of year. Holiday shopping and back-to-school are when advertisers pay a premium as they're all jockeying for spots. But look how lazy he was November-December, top tier earning times for YT.
Also, the older a video, the less it feeds YouTube algorithms so the less likely it is to be seen no matter the subject. Videos typically earn the most within the first 2-3 days of posting and then earnings taper off. This is also where he's just stupid about his channel. If he wants to earn a living off YouTube, he needs to put out more consistent product.
Member = Paid YouTube person, you pay each month for special perks, just like Patreon.
He says in that post that he has 443 patrons and channel members. He was at 366 patrons when he posted it, so 77 YouTube members. He lost 11 patrons since then so who knows how many YouTube members he lost as well.
Also, YouTube is way more stringent about monetizing than Patreon. Enough members complain that they're not getting promised perks and YT can suspend that option completely.
As for sponsorships, unless you're very popular and widely known (i.e. Ryan George, Brett Cooper) you usually need to reach out to various companies and actively look for them, they won't come to you. Maybe back in the day when he was whoring himself out to everyone, he might have put that on his to-do list but obviously he can barely lift a finger these days. His channel also doesn't scream professional and really doesn't have much of a tie-in that sponsors might think will bring them customers. So he could work a helluva lot to maybe find one little sponsor or affiliate.
So bottom line, he can boast about or buy or whatever all the subscribers he wants. His sparse, poor-quality content means little earnings. Even more important, he's not doing a thing to make a dent in the JW relligion or help people wake up.
Just my two cents...