Almost 4 year old is being HORRIBLE!

My sister needs some advice. I got a call from her this morning crying because her 3 year old has been acting horrible. He turns 4 October 6th and my sister states she wants to cancel his party because she isn’t going to reward his bad behavior (totally her decision).

He recently started school this last month and at first he wasn’t too bad. Now he doesn’t want to listen at all.

•Refuses to follow directions/instructions at home.

•Doesn’t want to go to his class room

•Doesn’t want to go to bed early

•Hitting/biting

•Refusing to apologize when does something mean

•Refusing to leave school some days

She doesn’t know how to help him. Anyone have similar situations? How do you deal with it?