Legal Question in Wills and Trusts in Illinois

Probably not. An unconditional gift (assuming without proof that this is what we have) once completed, vests absolute title in the recipient. The jewelry would have become your mother's to do with as she wished.

I agree with Attorney Prihoda. If your version holds up, the gift made the jewelry your mother's and she had the right to do with her jewelry as she saw fit, regardless that it was originally from your brother. If she properly conveyed it to your daughter, that should hold up.