if he likes poker, he probably can write about poker? potently, he can sell poker?
there are many poker aff out there...buy a .com for him, get a good custom design, do some basic keyword research, make him write about them, maybe videos too.
give him poker blogs and forums to join and be active there, after some time try to post your link to the site. fan pages too. im pretty sure if he likes poker he can manage all of that by him self and actualy grow an authority site....will take time but if he get passioned about it, sales will start to grow =)
ps: most poker players already have pokerstarts account so try to get aff programs from others...many =) any poker player would like to test new waters =)
again, this is tough niche but profitable....if u dont rely on google traffic and get other type of traffic you both can win in long term...specialy with recurring commisions....