The mother, Kendra, had jet black hair pulled into a high bun. Her face had a carved quality about it. Despite the high-necked silk gown she wore, Harry thought of Native Americans as he studied her dark eyes, high cheekbones and straight nose.
He learned them at our mother's knee. Secret and lies that's how we grew up."
This is what we know of Kendra Dumbledore... My headcanon is that she was quite a harsh mother, loved her children and raised them well, but strict and cold all the same. Remember a lot of children that grow up to be the kindest beings also grew up in the coldest darkest households.
We also know that his father killed three muggle boys in an act of vengeance. Cold blooded murder. And Kendra being a muggle born witch makes you wonder a bit. She probably hates her heritage a bit after muggles destroyed her family, her love and her children. She clearly struggled even more so now being a single parent. And then we know that she was killed by Ariana. We see in Fantastic beasts, Obscurials lash out when threatened or dare say triggered. Makes you wonder why she lashed out on Kendra that day. Who knows. Maybe Kendra had enough, and seeing Ariana's worsening condition and suffering, wanted to end it before it got beyond her control. She couldn't help her back then... but maybe she can help her now.
And I believe that Albus agreed with her to some extent, deep down. He tried everything to save her nothing can reverse the damage done by those muggles.
Whereas Aberforth isn't as realistic or pessimistic, doesn't see his sister as anything but his sister, thus being her favourite.
But what would their family dynamic be like if none of this happened? I see that in most fics they are depicted as happy... the parents in love, the siblings are very close and healthy relationships with there parents. But I don't think that would be the case at all.
Firstly, Albus would most definitely have been outcasted/disowned due to his preferences for men.
Everything we know about his parents would strong suggest this, and the evidence lies in Aberforth Dumbledore. His behaviour and response towards Albus and Gellert's 'closeness' that summer speaks volumes. This is learnt behaviour from parent to child. Albus learnt to keep secrets from a very young age, from his mother's knee.
Conclusion is if Albus dumbledore's family had lived without tragedy, tragedy would find him anyway, and the villainous potential this character has will forever be in my mind. Maybe I should write a grindeldore fic about this.