There were two ways to handle this, each acceptable: one was to carefully control his exposure in public venues and interviews so as to minimize his opportunities for "gaffes," the other was to get him some steady but intensive issues-tutoring so he cd turn weakness into strength:"OMG, that was a fantastic answer to an obscure question, this guy is awesome!" (BTW, Ron Reagan was a sharp and knowledgeable guy, but even his campaign recognized his tendency to shoot from the lip, and always kept careful control over his exposure.)
But, my friends, he has done neither. And it has HURT him, and after ~7 months of hard campaigning, it doesn't look like he will EVER get that he needs (needed) to do this.
The single thread running through all his blowups the past month or so has been his refusal to recognize his own weaknesses or vulnerabilities at the moment, and prudently either address them or minimize them. I sense that, at the end of the day, his (rather noble) instinct is: "Hey, just give me the ball again, fellas, I'm gonna pull this game out of the fire yet again." But when the other side has stolen your playbook and knows exactly what you're gonna do, that just is NOT the best way to win.