Bochur 2.0: WARNING… This is going to come across as harsh or just blunt.
Here’s the situation from my perspective:
Being a smoker or ex-smoker can be a deal breaker for some girls.
In these situations, it doesn’t matter to the girl if he’s a top boy because he’s out of the picture if he smokes or used to smoke.
(And I am guessing that he is in his 20’s and may not have a decade or so of smoke-free sobriety so even if he stopped a couple years ago, that might not be enough… for all they know, he could have just done it for shidduchim. Some guys start smoking again after marriage. Etc.)