My dad is too childish

I wish my father had treated my mother the same way he treats my step mother after my actual mothers death

My father never forgave my mother

He always held grudges against my mother. My mother always wanted to be treated and taken care of my dad didn't do that he hated her in front of us

Physical abuse and everything right in front of us.

How am I suppose to forgive my father and accept my step mother as my own mother (she always complaints that I don't treat her like a mother) my dad married her without me knowing it how does he even expect me to call her mom lol

Am I sinful for this. I internally hate both my step mom and dad. They're both together as a team making me feel like I'm left out. I wish I had someone who understands me in my own family but I feel very lonely and hurt.

Why did Allah do this to me and my mother.