Does the daughter of the deceased brother (who died before his mother) inherit from her grandmother if she has an uncle? And is it permissible for the grandmother to bequeath to her a portion of the inheritance not exceeding one-third?

The granddaughter (daughter of the son) does not inherit when a son is present, by scholarly consensus. Rather, she is completely disinherited by her paternal uncle.

There is no objection to the grandmother bequeathing to her anything that does not exceed one-third of the estate. This bequest is binding on the heirs, as it is made to a non-heir and does not exceed one-third.

A bequest to a non-heir is binding up to one-third without requiring permission. Anything exceeding one-third depends on the heirs' approval.

Matters of inheritance are complex and should not rely solely on a fatwa. Instead, they should be referred to Sharia courts for investigation.