What is the ruling on a woman marrying the maternal uncle of her sister's son, whom she breastfed, and having children with him?

If a woman nurses five full, satisfying times from the milk of the father of her niece's son, then her niece's son's paternal uncle becomes her paternal uncle through suckling, and it is unlawful for him to marry her, due to the Prophet, peace and blessings be upon him, saying: "Indeed, suckling prohibits what lineage prohibits." If the suckling is proven, they must separate, and the children are attributed to their father because it is a marriage of شبهة (doubt/near-validity). However, if the suckling was from milk other than that of the father of her niece's son, then there is no prohibition and no objection to the marriage.