Plot hole
Indiana drank from the Holy Grail in 'The Last Crusade'.
This should mean his aging process would be CONSIDERABLY slower than regular people's.
Therefore, we should have seen him look, sound and act pretty much the same as in previous movies.
However, Indiana has AGED to an old man!
What? Did the Holy Grail not have an effect on Indiana??
Don't tell us something, and then ignore your own story that mandates certain things to be a certain way, if you're not going to respect your own story's parameters!
Indy should've been as young as he was in the other movies, at least for all intents and purposes. He should NOT have been an old man - HE DRANK FROM THE HOLY GRAIL!