There is still something there in
@Tennis-Ball-Tony's point, I think. Barb has the choice, at any point, of saying "fuck it, Chris, get out.", and Chris would have to leave and make it on his own. And she has never done that, or as I understand it, has there ever been that high a risk of that happening.
The point isn't to suggest another mother-of-the-year award for Barb. It's just that once Barb goes, that probably won't happen to Chris again. As you say, there are various people who can help Chris, and some probably will. But they will probably help him in a fairly arms-length way. Whatever sense of belonging, being wanted or needed, or having someone there for him all the time, he gets from Barb, he will probably never get again.
I agree completely. There is also a sense that bills are "fuck up once and your screwed". That's not really how it works, in most cases. Suppose he forgets his electricity bill one month, or doesn't have enough money left over to pay it. They are not going to shut his power off the next day. They will send him a reminder notice, maybe tack on a couple bucks of interest, and he will pay it as soon as the tugboat gets in.
Since he will always get his tugboat reliably, in order for Chris to get in real trouble, he will have to heep looking at the bills coming in and saying "nope, not paying that."