I Dont see why he can't other than the continuous posession since it would be possessed by the post office or ups.
To be absolutely sure he could drive to Wyoming and they could ship from there. Then again it probably is driven or flown down to dia and out from there if he sends them by air.

I think he would be good to go. Nobody is allowed to open your mail as it is a federal offense so they can't really possess the contents. A bit of a grey area but just one more reason this law is total bullshit.