He mustn't just shove it in the box. There's considerable work to packing a bike properly. It's not that I've sold any bikes for couriers to pick up but that I bought all my bikes, every single one, from dealers at least two countries away, and so have repeatedly seen the right way to do the job.
Inside the box the pedals must be off the bike and in a sealed padded bag ziptied to two tubes so that the paddybag is suspended in a frame triangle, The handlebars must by loosened to be turned -- and ziptied so they can't move. Those two items are ziptied to the frame after it is thoroughly covered in round tubular stiff foam, which is itself ziptied on. Every frame tube must be covered, and the handlebars too, and the cranks. It's amazing what will bump around in a box and bruise your bike's paintwork distressingly, and what will bump into the box, ditto.
(http://www.audio-talk.co.uk/fiultra/UtopiaKranich0109/Baby%20comes%20home.jpg)
The pic from http://coolmainpress.com/AndreJute'sUtopiaKranich.pdf is an example of a properly wrapped bike after I already removed some padding. Notice the padded tube tied to the head tube for loose bits. It took me a good hour to clear all the packing off the bike, so you can imagine how much work it was to pack it properly.
Good luck.