my aunt and my mom crying, but my father and uncle were not crying Why does this happen?

My grandmother was hospitalized yesterday. The doctor said she might get a heart attack during the surgery. I saw my aunt and my dad's wife crying, but my father and uncle were not crying. My dad never cries. In school, when the teacher punishes us, girls cry, but boys don't. Why does this happen? I feel that men are emotionally very strong.