Tia’s mother is not royalty, but her people with the same blood have a gift to see the future at times. She did die and maybe Tia’s father didn’t say much because he misses her too much.
Spoiler alert just in case
Tia's mother is from the south they were like Nomads with special abilities
Another spoiler:
Tia's mother had the ability to somehow see the future despite knowing she will die soon she still choose to be with Gallahan and gave birth to Tia she died happily
And somehow it indicates also that Tia had the same ability as her mother (premonition something)
That she really didn't go back in the past but saw actually saw the future and changed it (this info still not 100% confirmed)
Wasn’t she like a dancer? Like kinda gypsy vibes?
Hmm I don't really remember if Shan was a Dancer or not since I read the novel a long time ago
So I have a theory. When ever we've seen a glimps of Tia's mother she is clearly dressed well. I have an interesting theory that she's run away royality from another country and either she actually died or was forced to return home and then died and Tia's Father can't talk about it at all. I mean why the hell would he not talk about Tia's mother to her ever?! Because if he tells her anything she might figure it out and put her in even more danger.