He doesn't say he doesn't, so I assume he does.

The problem is the way he got banned also blocks him from his shared auth, which in turn blocks him from purchases and device functionality:

The Damage: I effectively have over $30,000 worth of previously-active “bricked" hardware. My iPhone, iPad, Watch, and Macs cannot sync, update, or function properly. I have lost access to thousands of dollars in purchased software and media. Apple representatives claim that only the “Media and Services” side of my account is blocked, but now my devices have signed me out of iMessage (and I can’t sign back in), and I can’t even sign out of the blocked iCloud account because… it’s barred from the sign-out API, as far as I can tell.

Seriously, it's like a one page blog. You could have read it in the time it took you to make me read it for you.

You'd be amazed how many people are competent developers but have very little knowledge outside of what their job requires. I have friends in hiring positions and they see it all the time. Inflexible workflows and the complete inability to work if part of that workflow ceases to function are unfortunately common.

Apple, like Microsoft, Google, and others has a real web of dependencies for all its software. Even if he did back up all his important data, unless it was in an open format with open metadata it probably still requires an Apple program to open, which will require his Apple ID to be working. And every one of these big monopolists makes it really hard to fully export your data and metadata in a useful, unencumbered format because keeping people locked into their ecosystem is part of their business plan.

We're all doing the best we can to live in unregulatedcapitalismland while staying sane, keeping our data backed up, eating healthily, getting enough sleep, getting exercise, spending enough time with friends and family, and so on. Things eventually slip.