I reread Tunnel In The Sky comparatively recently. It creaked a bit, but held up. I don't remember Deacon Matson specifically. The whole thing was very reminiscent of Lord of the Flies, published a year earlier, one of the spectrum of books that crunched humanity down to a minimalist society. Whether this was meant to presage a post-apocalyptic world, or Heinlein was being optimistic about the human race, I can't say.

Most people -- kids -- make rational decisions about survival and sex. The society has problems, but survives. Bad decisions lead to bad outcomes, and brave people are rewarded. For the most part.

Not the book Heinlein should be remembered for, but a better-than-average sensawonda juvenile in the 50s.