https://www.amerdental.com/tubing-connectors
If you can't find them at a hardware store this company will have them. Also a dental supply / repair company near you will have them in stock.
Which handpiece is he going to give you? You will need a dental handpiece connector and section of tubing amerdental.com or perhaps he can supply it with the handpiece. Identify the drive air in and out in the tubing and splice it (air in) to a tubing that will fit your foot control. You will...