Why the qualifier? "for his age"?
Oh. Right. Because we all acknowledge he's aged from his prime. And regardless of how you feel about the study of gerontology, it's right there in front of our eyes.
For me personally, it will take a serious amount of suspension of disbelief to think that the man in the picture above will convince me he can do the same thing as the man pictured below. Which is what is required of the character.
Now that doesn't mean that there isn't a story here. But it
AIN'T going to be
Raiders
Indy V will be the study of age. Make no bones about it.
Even the Duke, couldn't get past it.