I'm a single mother, and have two teenage sons. They've been very close all their lives, and they still are. But in the past year or so, my younger son Dan has taken on a more dominant role, and it's almost like his older brother has replaced him as the little brother. My eldest son will go to his younger brother to seek his approval, ask his advice, and even obey his instructions. My younger son will sometimes literally snap his fingers and say 'Liam, go get me a coke". And my older son will obey without hesitation.
That's okay with me, it's their relationship. But my concern is that when they get into an argument or when Liam makes a mistake, my younger son will punish him physically for it. Like when Liam dropped his brother's new iPhone, Dan slapped him across the face so hard you could hear his teeth chatter. Or when Liam called Dan's girlfriend a b*tch, Dan backhanded his face in front of me. In these cases, Liam will just stand there embarrassed, as if he deserved a slap for being a naughty child.
They're grown up boys now, should I say something or let them sort their relationship out themselves?
Read more: My younger son slaps his older brother when they fight, and makes him do what he wants. They're 15 and 17, is it my business or not?