I am yet to find a fic that studies the dynamic between Grigory and Andrei/Alexei
It would be hell of a can of worms, you know?
He was sixteen when Irina died. Ilya said Grigory was strict with Irina, but he was a kid. Alexei was about sixteen. He would see it for what it was, abuse/domestic violence and all. I bet he hated his dad's guts.
Imagine that: you hate your parent. And the said parent doesn't even notice or pay attention because you are not the favourite child. The conflict can't break out because you want to scream and the parent just doesn't care.
Ilya: I hate my family, but I don't feel like I have the right to hate them, and still, I am a fucking tool to them, fuck my life
Grigory: This is fine. I am so respectable. I did such a good job. Good for me.