Academy/Minicraft does the best 1/48 UH-60s. There is no conversion set to make it into a medevac helo. You will either have to leve the interior as a standard slick, or scratch the stretcher rack in the middle. Here is a link to an Academy/Minicraft UH-60, listed as an L, it is actually an A model. http://www.greatmodels.com/cgi/display.cgi?item_num=mc11621
Hasegawa and Italeri both make UH-60As in 1/72 as well.
http://www.greatmodels.com/cgi/display.cgi?item_num=ha00433
http://www.greatmodels.com/cgi/display.cgi?item_num=it025
As an aside, are you sure he is not Army? USMC doesn't have medics, they are all Navy Corpsman and USMC and US Navy don't use UH-60s as medevac helos. US Army does have their own medics and we use UH-60As for medevac.
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