beta
**im not an expert just speaking from things I witnessed*
Im not making excuses for the mother, however after giving birth to a child the mother's mentality has a chance of fucking up. The hormones are unstable, causing all sorts of issues (especially mental), and the mother might never be the same as before in some cases.
This is no excuse, I'm on your side about disliking the mother, however here is a legitimate explanation for her behavior, seeing as she regretted it and loves her son genuinely. Or, if not, there is the other argument of her just genuinely being a bitch that calmed down.