Realistically, how would be Andromeda's relationship with Narcissa after the war?

People love to write about the sisters coming together and taking care of their grandsons together and all, but how realistic is that really?

Andromeda left their purist family to be with a muggle born, and the half-blooded child she had with him had a child herself with a *werewolf*. We know blood purists don't even see werewolves as people, let alone people good enough to reproduce with. Meanwhile Narcissa married one of Voldemort's more dedicated minions and served as a death eater herself for over a decade and remained in support of their sister who ended up *murdering* Andromeda's daughter and their only other cousin who stood up against purist ideals. This doesn't seem like something a grieving wife and mother with a grandson to raise by herself could easily get over in the name of sisterhood.