Depends on what the "treatment" is. When it comes to accountability and personal responsibility, they get the same. When it comes to other things, it's based on personality.
I had two daughters with completely different personalities, one you just looked at when she did something wrong and she would cry, the other was head strong. She once said she could not take a pill, it was crushed up mixed with jelly, she sat for 3 hours got up spit it out saying I told you so. She was 5 yrs old.
I don't have kids but I raised my brothers and they all all so different, and I treat them different.
It's like when they ask "Do you love me more than him?" And I always say "I love you all equally but I love each of you different."
It's like when they ask "Do you love me more than him?" And I always say "I love you all equally but I love each of you different."