Looks easy doesn't it...OK, some are naturals and I have met a few in 35 years of painting...a very few- but if you can do it then here's what you do.......If he used Diamond deluxe you can get the mix codes from General Motors for their paints, or you can go to NAPA for MS codes, or your nearest PPG auto paint dealer (I think that's Westco over here) and they have them, and get your paint & supplies.
Good Luck with your decision to attempt such a feat with a very difficult & expensive choice. Please let us know how it comes out & PLEASE post us a picture...