[Oh he noticed too, but he cares a lot less about Sanji. Between his initial assumption that Sanji's just a weakling and seeing him as "Mr. Prince" in Crocodile's prison, Smoker still barely gets a blip on his radar with regards to Black Leg.]

He was officer of the ship, if he didn't care that you went missing and why, he shouldn't have been placed in such a position. And I doubt that the Malnosso are so careless as to put someone there who couldn't cut it.

[Though... he doesn't include his own personal welfare in that, because... come on. It's one thing to care about a fellow pirate when you're on duty to help protect and look after them, but a marine enemy? That's a stretch.]