Nah I think it was just him not thinking and being extraordinarily self-centred. ADHD meds can be pretty nasty, but the idea of "normal pills" in a perjorative sense, and that "your condition makes you unique", is pretty irresponsible in my view. He's never had to expand a view beyond that from finding a mental illness incompatible with modern life. Thus ends up giving a pretty chilling "throw out your meds" message to the deeply unwell fans with personality disorders or psychotic conditions.
Even for ADHD, most people with ADHD won't get obsessed with something like minecraft programming. For most people ditching school to play minecraft will ruin their life.
If the video is meant to resemble his early school life, it really speaks to just how comfortable it was. School sucks, that's a perfectly normal pressure almost everyone faces. The anxiety of failing grades, or the prospect of no future is something that frightened everyone. But there's absolutely no tension in it for Dream because we know he miraculously managed to build a career of skiving school and playing minecraft with his friends.
That's not going to be an option for the vast majority of people in that situation, I can really take this video as a true expression of Dream's feelings about his life... from how cluelessly and naively self-centred it is.