Ruling on the marriage of a brother to his brother's sister through breastfeeding

A message has reached the program from our brother 'Abd al-Ghani Saleh 'Ali al-Salahi from the Yemen Arab Republic. Our brother says: I have a sister through breastfeeding, and I am the youngest of my brothers. I have an older brother who wants to marry this girl. Is it permissible for him to marry her or not? Please give us a ruling, may Allah reward you with good.
Answer: If this girl was breastfed by your mother with sufficient breastfeeding, which is five breastfeedings or more, then she is forbidden to all of you; because she is the sister of all of you, if the breastfeeding was five breastfeedings or more while the breastfed child was within the two-year period before weaning.
As for if the breastfeeding was such that you were breastfed by her mother, but she was not breastfed by your mother; rather, only you were breastfed by her mother and your brother was not breastfed by her, then she is forbidden to you, she is your sister and not his sister; because he was not breastfed by her mother, and only you were breastfed by her mother, so she is forbidden to you; because she is your sister through breastfeeding if the breastfeeding was five breastfeedings or more, but she is not forbidden to your brother; because he was not breastfed by her mother, and Allah knows best. Yes.