First of all, you should talk to him calmly, tolerate him as much as possible, listen to his own inner views first, and then describe your views: now is an open society, men and women are equal, boys and girls are the same, there is no discrimination against women, and we are all successors after the reform and opening up, so we should actively respond to national policies to ensure equality for all. Moreover, girls who go to the grave can also serve. Now they are all cemeteries, so there is no need to fight.

In a word, you need to make your father-in-law feel that the present society is an equal society, both boys and girls are the same.