My sister's DH is the head of their family, very traditional 1950s type marriage with DC. She treats him like he is her boss or father and he makes all the decisions. I am single no DC. When we are all together he is in charge, for example if we go to a restaurant he chooses where and when, then marches up to the table and tells everybody where to sit. This maybe made sense when their DC was small but they are older now and it's every situation even without the DC present. When I tried to push back and ask BIL not to dictate to me my sister became hysterically upset. AIBU?
Yabu - they are the family and you are only one person so if your sis wants him to be the boss he's the boss.
Yanbu - just avoid being with them all together as much as possible and see sister and DN alone
Or...?