Is it permissible for a man to bequeath all his wealth to his wife, thereby disinheriting his brothers?

It is permissible for a husband to gift his wife during his lifetime whatever he wishes from his possessions. However, it is not permissible for him to bequeath anything to her after his death, due to the Prophet's (peace and blessings be upon him) saying: "No bequest for an heir." Likewise, he should not gift some of his heirs or others during his lifetime with the intention of depriving some or all of his heirs after his death. This may fall under the Hadith: "Whoever cuts off an inheritance decreed by Allah and His Messenger, Allah will cut off his inheritance from Paradise."