Considering how most of these responses are telling you to continue with NC, I'm going to go against the grain and play devil's advocate.

You included the detail that your parents' business is failing and that that side of the family is broke, most likely to draw us to the conclusion that they are doing this in an opportunistic effort to get money off of you. Although this is definitely possible (and frankly quite likely) I feel it's also a possibility that they're not simply trying to get money from you. Their almost bankruptcy could be completely unrelated, or indeed it could have been that living in harsher conditions spurred them into guilt at the fact that that was how they left you to grow up.

As for their abandoning you, clearly that's just horrible of them to do, but (again, just playing devil's advocate) they could have been completely aware of it this whole time too. As someone with anxiety over a lot of things, I can't tell you why I struggle to do things that I know I very much need to do, even if I keep trying to remind myself that the longer I wait the worse it will get. They could have known what they were doing to you was completely unfair and inexcusable as parents, and they could have been fearful of how to approach their estranged son, telling themselves they'd do it eventually, only to realize that it's already been 20, 30 years and there isn't even a semblance of relationship anymore.

That being said, I still completely agree with what the other redditors said about you not owing anything to your parents. Whatever you decide to do should wholly be for yourself and those you care about. If you feel meeting your parents and trying to restart a relationship with that side of the family will cause more negative than positive to yourself, don't do it just for the sake of your parents or your brothers.

Anyway, it seems to me that you've pretty much already made up your mind and just posted here to seek validation, so what I say probably won't make much of a difference. I just thought I'd bring these points up for your consideration. Best of luck anyhow.