He could choose a way of managing the money that was optimized for simplicity. For example putting it all in a one low risk low return income generating instrument. It's hard for me to believe that the stress involved in picking up a decent cheque every month for the rest of his life wouldn't be outweighed by the benefits.

To me his actions are those of a "difficult" person. Very hard for a more relaxed (dare I say "normal") person to understand and rationalize. So I wouldn't bother. As others say, maybe that's part of what makes him different and special.