You're probably somewhat right. Probably wasn't immaturity on her part. Notice he insulted her in a way specifically designed to trigger her because it was her parents' main degradation.

That's petty.

As far as for why she doesn't full custody of thr kids, he's the rate guy who actually fought for custody and had a sig ificant financial advantage he could leverage. Most men don't have both either of those things. So your adduction about the quality of her parenting ability is undeserved. Not that we'd expect any different from you.