I completely agree with you, I really like her, I hope she finds peace.
Idk if she knew what FL has gone through, because I think she is assuming and projecting a lot.
Let's be honest. The FL is going to be in almost exact same situation with her. She loves the man that can kill her accidentally (exceptshe has secret power that prevents her from dying). And from Celphi's mom perspective if FL was in the family for love it is exact same situation with herself so she warns her. If FL is not there for love but power she still warns her since she can still die. It is very wise of her to warn the newcomer actually. And let's not forget how ML actually killed her accidentally and was burying her to cover up the accident when she awoke super powers ┑(￣Д ￣)┍
We can't also deny that FL was in that situation because her family tried to kill her, using ML's blood, not the ML purposely seeking her or anything. Plus FL sought the ML. It pays to listen specially when giving unsolicited advice, no matter how bad she went through. If I was in her place and found out I was simply being ironically arrogant, I would be embarrassed to filth.
She is not arrogant. FL is now saying willingly, suiting her assumtions. FL can now leaved whenever she wants but she choose not to do it now. And even it was about the start of their relationship , when she went to see for ML's help she did not know she could be killed, if she did it highly doubt she would choose him as an option. Celphi's mom's warning is a good thing in every situation. Being alert is always good when it is about death
But the difference is FL already died and went back. She has already been there.
I'm not saying Celphi's mom is arrogant. Just ironically being or sounding like one because she gave a one sided advice.
It is maybe unpopular opinion buy I actually like Celphi's mom. She lost her husband and we don't actually know the reason for her leaving her son. She doesn't have second life or immunity like our female lead and she lost her loved one already. We don't know actually now this "curse" came to family as well. Also her reaction is understandable as well . She was trying to keep low profile and suddenly "the elite" came to her neighborhood and probably cause some questions about her "roots" in the neighbourhood. I don't think previous grand duchess, the mother of the heir would leave all these things without enough reason . And especially there must be reason for her hate and I don't blame her without knowing