To the best of my knowledge catfish don't "pair" for one - they just scatter eggs and hope some survive.
I've also heard TSN's are some of the most aggressive catfish out there, and in any fish mood becomes more violent with breeding season.
There are TSN hybrids out there, so I'd imagine it's doable - but don't see it happening in anything short of a few thousand gallons worth of water?
EDIT: There could also be somthing else in this guys tank that's doing the egg laying and he's just mistaking it for the TSN - though I don't know what with those kinds of predators living in there.