My paternal grandfather was known for his crying, AND a very strong mind, quick temper, and dominant personality, so your have to say the link between crying and weakness some mentioned isn't so straightforward.
My father I never saw cry at all, and in the whole of his adult life I'm told by my eldest sibling, who may have witnessed this, he cried at the funeral of his best school mate aged forty, and (she said she'd been told), the death of his first born child at five minutes of age. He was very strong too, though whether stronger in his mind than grandad I don't know, though I guess he must have seen showing emotion as a weakness.
(I'm a blubber, but mainly on happy occasions, though some funerals too)