[...Lack of interaction. She phrases it so delicately, but Nier gets the point rather easily. He's simply not a part of her life. He doesn't know the story and he doesn't feel inclined to ask, but it's nothing good. That's obvious. As a result, he simply nods along.

At least until she starts sounding resigned. He isn't sure what she's done, but it can't be worthy of a parent's lack of... presence.]

No matter how complicated this might be, you're making it sound like you deserved this and I don't buy that for a minute.

[He huffs out a breath and when she grips his hand, he turns his attention up to her, offering her the same in return. Is it reassurance? He doesn't know how to give someone in her situation that. She's got a lot brewing under the surface. He never would have guessed it from the initial meeting. He almost doesn't believe in the present, but she wouldn't have anything to gain from speaking false.]

You don't deserve it. Sounds to me like they didn't know how to handle things. And because they didn't know, they were either too afraid to figure it out or they just didn't care enough to try.