This may not be a popular reply, but if it were left to me I would put his medals up for auction, and have the proceeds donated to a suitable charity, such as the RAF Benevolent Fund. The suggestion that his papers, etc, go to the historian mentioned above is a very good one, but both the RAF Museum and the Imperial War Museum are awash with medals, and unless there is something particularly rare among them it is likely they would just disappear into store rather than go on display. Some auctioneers are willing to waive or reduce sellers' commission fees if items are being sold for charity so that would be worth exploring should they go for auction.