Ageist as fuck.
Also…not sure how many people today know this but the longest ever serving president was confined to a wheelchair. Unassisted mobility isn’t a requirement to run this country.
I wouldn't say conceal because people knew about his disability. What he did do was not allow himself to be photographed in a wheelchair (only a handful of photos of him in one, I think). Instead, if he had to stand, he used braces and a walking stick. Usually he was on a simple chair though.
There IS disagreement over this. He definitely tried to minimize his disability which can be seen as concealing it. But he did reference to it, used crutches in public, and often had someone helping him. The White House was wheelchair friendly too. So I wouldn't use the word "conceal" for it.
Considering he had to deal with image and appearance fueled Hitler, who‘d mercilessly had mocked „the cr*****“ for laughs and humiliation, that was a smart move.