Here’s what I’ve been able to learn: David passed away while under hospice care, per his sister. Per a thread on the Education Forum, sometime prior to his death David shared he had been carjacked at gunpoint in Vegas, where he was residing. A gun was pointed in his face, he was forced to lie face-down on the pavement as the 3 carjackers drove away in his Honda. That has relevance to my OP question because David related that as the gun was pressed against his head, all he could think was (I’m paraphrasing), “All of my work and it will never get published.”
Perhaps that incident was the impetus he needed to spur him to make arrangements for his work to be shared posthumously. Just hopeful conjecture on my part.