Why do they keep doing this?

So after friday nights incident my dad didnt actually leave and everything seemed to be fine
we all acted like nothing had ever happened.

But today
My brothers decide to start arguing again while we're having tea...
well they werent exactly arguing
but tham laughs at george
and george storms out throws his chair over and slams the patio door behind him

this causes my dad to stand up shout [i dont remember what he said] and go upstairs
then comeback down a couple of minutes later
and leave

My mum gets tham and george back and just tells me to carry on eating my tea...
when they come back tham starts saying he did nothing [when he was clearly the one who started this] and blames it all on george

so george shouts at him telling him to shut up

and tham carries on

after a while tham storms off aswell
but unfortunately is still here to cause arguments

my mum keeps saying she can never forgive them if my dad doesnt come back
as my dad never usually storms off its normally my mum.

i noticed during the rest of our meal she kept staring at my dads food on the table and looking rather upset

I cant believe my brothers keep doing this
they have ruined our family over the years

I admit i have done things at some points
but even my mum says that it is those two and not me

I really hope my dad comes home :'[