I don't know why you're asking me, as I am not an authority on such things. But, since you have asked me; he responded that "I would like to see it first, but I can see no reason why you should not upload it to the DLS." If I were asking, I would have provided him with the asset, (which you have), and then awaited a response (which you have). I don't know why he hasn't gotten back to you.
Now Sniper would say that it's none of anybody's business unless they have a badge and a warrant. I note that Narrowgauge has not been on the forums since August 9th, and that is a concern, given his 'advanced youth'.
Have you tried to contact him again? He and I don't regularly communicate, so I can't help you there.
I think you have met the conditions he stipulated; in that 'he did receive an advanced copy' and he has not written you to change his permissive "I can see no reason why you should not upload it to the DLS." I would conclude that is permission to upload, assuming that if he received an advanced copy he would have protested if there was some horror he couldn't abide. Sometimes silence is considered consent. Sometimes not, I am no lawyer, and I don't have a badge or a warrant.
These are just opinions of course, but I'm sure you've launched a thread that will garner many opinions.
I am more concerned for his welfare right now, so if anyone knows anything about the subject, please post.