Is a wife forbidden to her husband if she is the sister of his brother through breastfeeding, and he is also her paternal uncle through breastfeeding?

Suckling establishes the same prohibitions as lineage, as the Prophet, peace and blessings be upon him, said: "What is prohibited by lineage is prohibited by suckling." Thus, the suckling child becomes a son to the nursing woman and her husband, the source of the milk. This applies specifically to the suckling child himself, not to his siblings. Therefore, your grandmother suckling your wife's brother does not prohibit your wife to you, nor does it invalidate the marriage. Your wife's brother becomes your paternal uncle through suckling, but this does not make your wife your father's sister through suckling, nor does it affect the validity of your marriage to her. Five satisfying sucklings are required for the suckling to be prohibitive.