John Senior wasn't wearing a knight's heavy armor, just hard leather armor.
It wasn't that he was too old to wear heavy armor… The lifespan of a professional was much longer than a normal person, and even aging was much slower than a normal person's.
Although John Senior was in his forties, he now looked, at most, to be in his early thirties, and that was because he had purposefully grown a full beard.
If he had shaved off his beard and gone out on the street with his son, John Junior, people who didn't know them would have thought they were brothers, not father and son.
Having someone help with putting on armor was a ritual, usually done by a knight's apprentice, and if a close offspring was asked to help with it, it was to tell them that it was almost time for them to go to war, and it was time to get used to the atmosphere of the battlefield beforehand.
John Junior was thrilled to hear his father's words.
