You'll do well to find one flavour that matches a specific brand, but the generic tobacco ones I've tried are nasty enough to be passed off as cigarettes. If you're going to get a few, suggest not going mental with choices, but get some tobacco and then take him to a shop shortly after Xmas. He should be able to try some flavours and also he's going to have to get used to going to one instead of buying fags.
You need to think about the strength as much as the flavour, because if he doesn't get that throat hit and relief from nicotine craving he'll soon revert to cigs.