For something like this, experience is the best teacher. Try to get your hands on some dro, that'll open his eyes.
Experience -> tolerance -> preference -> Oh I get it now... He's gotta spend more time with the herb to better understand the fine details that set strains apart. It's like someone trying beer for the first time. Initially almost all beer seems the same
Of course they aren't the same... They might be the same to him because he has only smoked a few times, but if he were to start smoking a lot more than he would definitely see the difference...
Who cares? Unless he wants to be some kind of connoisseur and have every minute of his life revolve around weed let him think what he wants to, not like he's forcing his opinions down your throat.
Does he have access to the internet ? do you have access to the internet in his presence well then just type sativa indica into google or some shit, educate his ass :L
Hell yeah skunky's back! I missed you man... you were like the first person to be nice to me on here. You're like the coolest blade I've ever met, glad to see ya back Can you share where you've been' or is it all hushush