Depends on the person. If he seems to be living it pretty openly, I'd imagine he has a sense of humor about it. If he does, pick his brain and report back to us with the hilarity.
He/she has not openly discussed any sort of porn involvement with his/her friends, but neither do they appear to have made a particular effort to hide their connection, having used their real life name as producer and 2257 contact for the non-animal videos they directed.
I'd tell every friend we have in common and wait for one of them to get drunk enough to ask him about it.
I may already have done that, finding it impossible to keep the staggering revelation to myself.
Then I would jack it to his sister blowing dobermans and having horse cum gush out of her holes.
Dog-wise, they seem to favour Great Danes. As for horse cum, the description of one of the sister's movies says "Without any problem she swallows the big load of horse semen", so I guess there is plenty to satisfy your tastes.
Personally, I'm more preoccupied with trying to pin down the chronology and figure out which of this person's cute teenage half-sisters was inside the stepmother when she filmed "pregnant dog lovers".
Ooops, did I forget to say "hypothetically".