Is it permissible for the deceased to bequeath a sum of money to his brother's children if his wife agrees, knowing that they inherited by ta'sib (agnatic inheritance), and given the saying of one of the muftis, "There is no bequest to an heir"?

In Sharia, intention alone in a gift (hiba) is not considered valid unless accompanied by a statement or an action, and the gifted item must be taken possession of by the donee during the lifetime of the donor. A gift conditioned on death is considered a will (wasiyya). If a deceased person said before their death, "To so-and-so, one thousand dollars," intending it as a gift, but it was not executed, then the gift is void. If the intention was a will, it is not valid for an heir unless the other heirs approve it. If a wife claims her husband willed half his wealth to her, or that she was a partner in his wealth, she must prove this with evidence. Matters of inheritance are serious and complex and must be referred to the Sharia courts for investigation.