lol man! why are you chickening about sending a PI? How is that gonna harm your business? Besides that why on earth do you need to send it by DHL or FEDEX? why cant you just send it by email. Its easiest and also quickest to do so if you make your PI on your computer and send it as attachment by email. Even if you make your PIs manually on hard copy (paper), still you can scan it and send it to him by email as a PDF file attachment. Isn't it?
A .pdf document should be completely enough. Or you can fax it too. P/I is basically only an order confirmation, that includes the price and conditions you agreed on, bank information, full address. This is in order to let him know how much he has to pay, to which address, and where can he pick up his shipment. That's it.
I think printers and faxes are not unknown in Ghana. I am just simply curious why does he insist on courier service (besides this he can absolutely be a honest businessman). Please tell us if you had found out!