First, I must commend your courage to have shared this. Many of us having scars from family that we often choose to endure.

Second, The teenage stepbrother is very innocent unless if eventually his mind gets poisoned about you people.

Third, you were very obedient and did your best. My advice is that, realize and understand there is a difference between responsibility and help. Irrespective of the hurts and the pains, you will have responsibilities towards your dad, the same way you cannot repay his upbringing in aspects you appreciated as a growing child.

And finally, some men do come back home, time will tell