Or rather … Boy, you should know that I’m more than wealthy enough. At my age you don’t need such a large amount of money any more.” (Burkhart)
In his early days he had been an elite adventurer making heaps of money and after his retirement Burkhart-san served several noble families. Therefore it seems he had amassed a fortune that rivaled that of nobles and their likes.
Thus I was told that he didn’t need half of the share of the looted prize.