1,943. Betrothing the Yevama's Sister

Yibum v’Chalitzah 7:7

If the brother who made maamar died and he had a wife, both she and the first fall to the brother who is married to the first woman’s sister. The woman who was given maamar is relieved of chalitzah and yibum because she’s the sister of the surviving brother’s wife. The other woman should perform chalitzah to the exclusion of yibum because the maamar does not effect marriage enough to relieve another wife of her levirate obligations.

Yibum v’Chalitzah 7:8

If a brother betroths his yevama’s sister, he is advised to wait and neither divorce nor marry her until another brother performs yibum or chalitzah with the yevama. If another brother performs yibum or chalitzah, or if the yevama dies, then the first brother can marry the woman he betrothed. If all of his brothers die, he must give a get to the woman he betrothed and perform chalitzah with the yevama. If the woman he betrothed dies, the yevama becomes permitted and he may perform either yibum or chalitzah. This is true regardless of whether the betrothed woman died before or after the brothers died.