Odds are if he died in 1947 he never did receive his medals.It took the government a long time to distribute the millions of medals that were awarded after WW2.
Technically, as a grandchild you are not next of kin. Use the site I posted, follow the instructions, download the Archive's form SF-180 and fill it out with your great uncle requesting the medals. He is technically next-of-kin. Use the correct address from the link, and include a xerox copy of his discharge papers showing the medals he was entitled to.This isn't necessary but is helpful to the folks there.Expect a long wait.
Alternately, you can buy WW2 issue occupation and victory medals relatively cheaply.If you don't want to wait for the free one's from the govt. a set of WW2 issued medals would cost you no more that $20 on eBay.If you want to go that route contact me off this board and I'll find a couple for you on eBay.