I think I can forgive someone using the language of their past self when reflecting upon that past. In the context of the paragraph, I think it's fair to say that "which worked" means something more along the lines of "and things did get better." Maybe he could have improved his word choice in that instance, but I don't think that negates everything else said.
I can already hear you saying "but that's not what he said, and that was his choice of words." And to that, I point to one of the key lessons I learned in college philosophy: questions of meaning come before questions of truth. In this case where one short two word sentence does not fit the rest of what he is saying, I think it's best to ask what they could mean that would fit.
Every piece of advice for dealing with procrastination will lead to “just doing it.” This is because “doing it” is the end goal when not “doing it” is the problem. If their advice was to “just feel/do better,” then you may have a point, but they didn’t. It wasn’t fleshed out, but they said to learn emotional regulation to better enable the ability to “just do it.”
That is genuine advice, as a growing amount of research is finding that procrastination is tied to a failure in emotional regulation: https://www.bbc.com/worklife/article/20200121-why-procrastination-is-about-managing-emotions-not-time
I can’t say that this advice is relevant for those with ADHD, but the fact that your first response wasn’t to investigate whether their advice was useful, but rather to try to downplay it as not advice at all strikes me as insulting to those who have used the times that they can be productive to work on themself and their emotions, and displays a desire to have problems to fix rather than a desire to fix them.