As a retailer, if he doesn't engage in anything the fda considers to be manufacturing, he should be good. Basically selling sealed packages off the shelf. Of course he won't be able to put anything together or create kits, but he could "bundle" necessary stuff together, I would assume.
I find a problem (with selling anything past the due date) in that even no-nic is considered a "tobacco product" and that includes the definition of (paraphrasing) 'anything intended for human consumption' with an ecig. And the same problem with the balloons and nitrous oxide case - where circumstantial evidence, rather than any subjective intent of the vendor, is considered. [again, this being the cases if no PMTA's are accepted - but with acceptance, I don't see a problem.]