Emily wrote:

I'm guessing that when he got his ATP, he should have surrendered his
commercial but didn't for some reason.

one pretty good reason not to surrender a certificate when you upgrade
it, is if said certificate has a rating which you do not want to give
up and which is not covered by the new certificate. Although this is not
exactly germane to this discussion, I did keep my old private certificate
(obtained under 61.75 (*)) even though I now have a commercial, because
said private certificate still has my glider rating on it; could it
be a similar situation?

--Sylvain

(*) before someone jumps all over me quoting 61.75(b)(3), whereby
you cannot get a certificate under 61.75 if you already hold a US pilot
certificate, nothing prevents you from keeping it after you get
a US certificate. But I digress :-)