Is the division of the mother's gold between the daughter and the younger brother only, while depriving the elder brother, who is well-off and residing abroad, legally valid, especially since half of the gold belongs to the younger brother?

The inheritance is divided among all heirs. No one is to be disinherited except in the presence of a legal impediment, such as difference in religion, murder, or slavery. If these impediments are absent, then no one can be deprived of their inheritance. If the youngest brother bought half of the gold and gifted it to his mother during her lifetime, it becomes her property and part of her estate. However, if it was a debt, it must be paid first, and then the remainder is divided among the heirs.