The Arrowverse has featured several superheroes who, just like in real life, some are parents who simply raise their kids better, while others would never earn the Mom / Dad of the Year award.
Parents do not always have to be related by blood to their children to be great moms or dads. Joe West is a good example of that. He took Barry from the Arrowverse into his care when Barry’s mom died and his dad ended up in prison.
Joe of the Arrowverse raised Barry alongside his own daughter Iris (and son Wally to some extent), and he doesn’t seem to differentiate between them. He is always there for his children when they need him and gives them good advice.
All Moira did was protect her children, who were the most important people in the world to her. She proved it once and for all when she sacrificed her life, offering it to Slade Wilson in exchange for Thea and Oliver of the Arrowverse.
Oliver’s life from the Arrowverse was filled with drama, and when he found out he had a secret son, it was a lot to take in. Some men fled, but Oliver was determined to meet his son.
Not everyone can sacrifice their happiness for the sake of their children, but Oliver of the Arrowverse did. But when William’s mother died, Oliver took care of William. Their relationship was awkward but they became a true family.