I dunno. I don't think that attacks on the person who smokes help at all - it just humiliates them and is, thus, counter-productive. Everyone has to find their own time and way to quit.
Perhaps a different tack: get them a good vaping kit, like the 510, 901, 401, etc., plus a bottle of juice in a flavor you know they like. Tell them that it's a present. You got it for them for times when they want to smoke but can't, e.g. when they run out of cigarettes; if their throat is sore from smoking too much the night before; when cousin Cindy is over who's asmatic, etc. It's NOT for quitting, it's just a way to "smoke" more. It may sit on the shelf for a good while unused, but at some point, your family member will get curious and try it out. Perhaps, it will happen for them on a cold and otherwise dreary night when they can't sleep.
Talk up the pleasures of vaping to them, in the mean time, while the kit is still on the shelf. Tell them about a new flavor, or how much more vapor you get with VG. Vape around them and ENJOY doing it. At some point, they'll have a moment of disgust with the analog in their hand, and will give vaping a shot.