I'm not sure what you mean; that was exactly my point. His exposure was likely minimal (I can't recall anything suggesting he was close to any criticality assemblage tests), but his exposure level is still more or less irrelevant. It's basically impossible to separate anyone involved in the Manhattan project that didn't die immediately from exposure from expected background population cancer rates.
That's stated pretty explicitly--even for those few most directly exposed in accidents--in the discussion section of the paper you link (which my first linked paper was a followup study to, 20 years later, btw), and it was found to be true in the larger population of nuclear material workers in the second paper (who were, indeed, working in an environment where much more was known about how to control the dangers of what they were working with).
That's stated pretty explicitly--even for those few most directly exposed in accidents--in the discussion section of the paper you link (which my first linked paper was a followup study to, 20 years later, btw), and it was found to be true in the larger population of nuclear material workers in the second paper (who were, indeed, working in an environment where much more was known about how to control the dangers of what they were working with).