Is it permissible, Islamically, for a man to bequeath a share of his house to his deceased brother's impoverished daughter—whom he had promised her brother he would grant an apartment—equally with his own children?

A niece is considered a relative (Dhu Rahim) who does not inherit. However, it is permissible to give her some money during one's lifetime, or to bequeath something to her, provided that the bequest does not exceed one-third [of the estate] unless the heirs agree.