Q: My sister married twice. She had three girls from her first husband who married another woman and had three sons. The first two brothers suckled from my sister while the third did not. The third son whose two brothers suckled from my sister proposed to one of my sister's daughters from the second husband.
Is it permissible
for the girl to marry the third son who has not suckled from my sister?
If this son has not suckled from the girl's mother in a way that makes their marriage unlawful, it will be permissible for him to marry her. The suckling that renders marriage unlawful is suckling for five times or more during the first two years, and one time of suckling is when the baby holds the breast, suckles milk and leaves it to take a breath. When the baby holds it again, (Part No. 18; Page No. 362) this is counted as another time, and so on. Consequently, this man's two brothers suckling from the girl's mother does not affect his marrying the girl. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.