I can't imagine how awful his friend and boss feel right now. He was behaving extremely erratically on his final stream to the point that they dropped by at 1am (granted that's more like 3pm in typical chess player time) to try to get him to stop playing, calm down, and just go to bed. They're obviously going to be asking themselves if they could have done more. The same is even true of Hikaru who recounted his last conversation with Danya, which was again about trying to help him up, and he teared up while again wondering if he could have done more.
And the catalyst for his decline was the cheating accusations. Yet the one 'mitigating' thing for Kramnik is that Danya really fell out of touch with reality with regards to the accusations. He made it clear that he felt many, if not most, people felt he was cheating. But in reality, basically nobody did. Kramnik has become basically a meme to the point that his accusations hold about as much weight as being called a naughty name online.
Of course from Danya's perspective it was going to be much more painful because he mentioned that Kramnik was one of his chess idols growing up. And people don't understand the amount of work it takes to become very good at chess. To then have one of your idols turn around and claim you're cheating, which is essentially pissing on all your work, is going to sting. And Danya had an immense, substantially more than average, amount of reverence for the title of world champion, which he felt that was causing people to believe Kramnik.
He felt the world was turning against him, but it simply wasn't. And the catalyst for this change was the accusations.
