Here's another option, just for consideration. With that kind of budget, you have some flexibility as others mentioned.
Retirement may be a time for him to enjoy hobbies, or in some cases even relive a second childhood. (look at the prices folks pay to get toys from their childhood.) Why not use some of it to get him a nice folder to carry- and I believe you can still get a hell of a nice folder for a couple grand. And then take the rest to get him something like a nice bowie, so he can play cowboy again. Or even a presentation pipe tomohawk if he played indian. Or a sword if he fancied himself a knight in shining armor. You'll have to know his personality whether he'd appreciate something like that, but maybe ya hadn't thought of it.
My dad has been going on a similar phase, buying up old western guns. He just got a lever action 1873 Winchester, and would really love to get a Sharps or other buffalo rifle...