This is nothing more than the sin of pride.. He does not want to be helpless or lose his “quick mind”
How sad to be so proud of who you are and your work that you will kill yourself rather than need other people or “spoil “ your legacy
With VERY FEW exceptions, each and every one of will have times that we are helpless and need to rely on others; likewise, those of us who live long enough will experience memory loss.
As "unfair" as this may seem, we must realize that this is EXACTLY the way God created us. Had He wanted to create us like some insects with a very short and defined lifespan He certainly could have, the point is that He didn't.