Cute Overload: Father cat supporting the Mother cat giving birth

[The Velveteen Ocelot]

7. The mother and father cats are probably residents of the same house

and therefore had been friends before they got busy, and are attached to each other. So dad cat was affectionate toward mom cat because he always was anyhow. Male cats can be very attentive toward kittens, too. I've seen kittens try to "nurse" off their dad, who wasn't bothered by it at all (they were just sucking on his fur).