The ruling on a child who was breastfed by his father's mother

A man has a brother and a wife. At the time of birth, this wife passed away and gave birth to a son. The grandmother of the infant, who is his father's mother, is an old woman over sixty years old. When the child's mother died, she breastfed this child for two years and produced milk for him. The second brother has daughters. What is the ruling regarding these daughters in relation to this child?
When the old woman breastfed the child, she became his mother. And if she is his mother, he becomes a brother to her male and female children. So, the female children will have him as their maternal uncle, and the male children will have him as their paternal uncle.And the evidence for this is the saying of Allah the Exalted: [Surat al-Nisa: 23] And she breastfed him and her milk flowed to him, so he suckled from her.