Typical manga wish fulfillment. The kid says a few magic words and her parents start reconciliation. Though she probably recorded the conversation to show her mom too.
The characters have bio pages in the LN, because of course they do, she's 120cm/3ft 9 inches. When your main heroine is 140cm, the "short" character needs to be tiny.
He won't do anything that would corrupt Char, and Char has a like permanent feed on him so he can't be sure what she'll pick up. He could probably block it, but having to explain why would be an issue.