Thank you all again. It really is helpful to have this much experienced insight. It's hard for our son (okay, and me, too) to stay patient and take it slowly.
We'll see how things go from here. Fortunately, he's got a good summer team lined up with a coach who knew him well enough to save him a roster spot without doing the fall tryout. If he can stay on his current course, summer ball could be good. We just won't have the kind of immediate track record/measurables to share and get coaches motivated to go see him at the summer tournaments.
That's part of why I was asking my question on this forum. Heading into the summer, it's possible that his return from cancer will be the only story he's got to tell.
Anyway, thanks again. This has been great.