If you think it should work like the flesh to stone spell, then ...hmm... The person seems dead but isn't dead. The effect of scry is a "magical sensor" that can see a "creature". If they're not dead, they're still a creature, and can be scried, I say. But the basilisk's description doesn't say much about its petrifying gaze, so the DM is free to decide regardless.
Heck, isn't it more fun to allow scrying? Wouldn't a DM want the party to be able to see the stony form of their missing companion, in an unknown location, about to be smashed to bits by some diabolical contraption?