Depending on how many "several years ago" - upgrades did not exist at the start of the FF programs (in the 1980's). Before the FF programs with upgrade capability - agents from DCA would upgrade me into the empty FC cabin - since they knew me from being a very frequent customer. Maybe this was the case with your father - 20 years ago. Also - FC may not have been completely full - after all Elite upgrades were process (rare - but it still happens).

Do not know the facts here - but it could be that the person knew they had been upgraded and the "power trip" gate agent held off on giving out the new boarding passes - which likely ticked off the person referenced.