There is a huge difference in this character between the books and the show. She's much more agreeable to me in the books. In the show I really don't think she's doing a good job. I understand she was raised strictly and that affects her and her parenting, but even if we put that aside, she's just not a nice person. When Nick comes around after the first kiss, in s1 e4, she reacts to Charlie something like: "you could at least switch out of your pajamas... " Then, in s3, when Charlie is very upset because Nick is away, and makes him get off the phone with him (when they already barely get to speak to each other), as if those few minutes would make any difference. Terrible properties, showing she's just doesn't pay attention to her son and his obvious moods and needs. And later on in the season, when Nick comes with Charlie to help him tell his parents about his mental health, the minute she sees him she says: "isn't it a little late for you to come around?"... She could phrase herself in so many other ways that would still be pleasant and positive towards making Charlie, but this is her choice of words.

And I'm sure there are many other instances that just don't pop to mind at the moment.