I mean...yeah. He's not wrong. Once you give up being the parent, it's the child's choice if you suddenly want to be one again.
It's a case per case basis that depends on the person. Personally, I think mom deserves all of this, but also he should eventually try to reconnect somehow after she clears up her karma.
She seems to genuinely feel bad, so I imagine that she probably won't do this to him again in the future. Though I wonder if she knew about the origin of the curse or it's just the Duke?
On that subject, isn't it a bit too late for the royal family to compensate the Duke for the curse?