Bochur 2.0
I don’t know where in the world you or your refused friend are.
Here in the USA, the Surgeon General released findings on the dangers of smoking more than 50 years ago.
I would not our daughter(s) marry a smoker or former smoker. Who knows what health damage lurks in his body that will surface later.
The fact that the former smoker quit is good, that fact that he ever smoked, with or without parental permission is bad.
Furthermore, in the era of $8-10 per pack of cigarettes (they were 40 cents when I was a teenager), a bochur who wasted real money on cigarettes is not someone I’d trust to handle family finances that could affect my child and grandchildren. The smoking shows an inherent weakness.
This is not the same as those mentioning gedolim, rebbeim who are in their 60s and older that smoke. They got hooked when smoking was acceptable, cheap and all the medical dangers unknown.