happen about {something} = happen in respect to, in regard to, regarding {something};
I told the landlord about the leaky roof, and asked him what will
happen about it. He said he would hire a roofing contractor to fix the leak.
The language of laws which are supposed to govern the behavior of
industries is often drafted by lobbyists for those very industries!
But little will happen about that, I'm afraid.
happen to {someone, something} = befall {someone, something}.
He committed a crime.
-- What will happen to him?
He will go to prison for five years.
The house was ruined in the flood.
--What will happen to it?
It is beyond repair and will be demolished.
She is in surgery now.
--What happened to her?
She fell off her bike and her head struck the curb.