Is it permissible for a brother who was not nursed by his maternal aunt to marry his maternal aunt's daughter, knowing that his sister was nursed by this aunt?

Whoever is suckled by a woman five known sucklings becomes her son through suckling, and a brother to all her children. This is indicated by the Hadith of Aisha, may Allah be pleased with her, which mentions the abrogation of ten sucklings by five known sucklings for prohibition. A suckling is defined as latching onto the breast, sucking the milk, and then letting go. A minor interruption does not break it, and moving from one breast to another does not make it more than one suckling. If you were suckled by your maternal aunt five sucklings, then you are a brother to all her sons and daughters, and it is unlawful for you to marry any of them. The ruling of suckling pertains specifically to the suckled person and his children, not his siblings. So, if your maternal aunt's daughter, whom your brother wishes to marry, was suckled by your mother, then she is his sister through suckling, and it is unlawful for him to marry her. However, if she was not suckled by your mother, then there is no harm in their marriage, and your suckling from her mother or her siblings' suckling from your mother does not affect this.