Is it considered legally forbidden (haram) for a husband, while ill, to deed his house to his wife out of fear for her from his brothers after his death, especially since they have not had children throughout their marriage?

A gift made by a sick person during a death-illness (marad al-mawt) is subject to the same rules as a bequest (wasiyyah). It is not valid for his wife unless the heirs ratify it, due to the Prophet's (peace be upon him) saying: "There is no bequest for an heir."