Its nearly impossible to guess on what he may have had. But looking at it as new equipment, you can get a RCBS kit for about $300. Dies are about 35 to 55 each. Brass runs about $40./100 on average for new. A good digital scale is around $250. Cheaper bullets run about $30. per hundred. Powder runs about $25./pound. Then all the specialty tools would easily double the cost of the original kit. Then if he was anything like me, he has a lot in duplicate.
If its all in good shape, 50% of new is a reasonable. I see stuff selling for well above and BELOW that on other websites and Ebay
Good luck, and if you get it, there is a market for all that stuff out there.