(A) at 79 years old, it should be no surprise that Trump regularly gets bruises on his hands - and most likely elsewhere - from the sorts of regular bumps we all get during the day that don’t bruise a younger person, for the simple reason that this is what happens as one gets older and ones skin gets older, and has no bearing on one’s mental fitness, and
(B) given Trumps vanity, it wouldn’t surprise me in the least that he would try to cover up those bruises.
When my FIL was 79, he was still very active - and he was with it mentally until he was 89 - and he got bruises like that all the time from the yardwork and auto repair he did.