Must a girl return jewelry given to her by her deceased mother, with the mother's consent, after her sisters demand it back and reject the gift?

"Equality among children in gift-giving is obligatory due to the hadith: 'Fear Allah and be just among your children.' However, if there is a legitimate Sharia-compliant reason for preferring one over another, there is no objection to it, such as if the child is poor or in need, or if another child is immoral. If the mother had no legitimate reason to single out your friend with the jewelry she gave her, then the rest of her children have the right to share in that."