Is it permissible to marry one's paternal aunt's daughter if the paternal aunt breastfed the elder brother, but the mother did not breastfeed any of her children?

There is no objection to marrying one's female paternal cousins. Marriage is only forbidden for a man who was suckled by his paternal aunt from marrying her daughters. As for a man who was not suckled by her, her daughters are not forbidden to him. The decisive factor is only suckling, and the suckling of an elder brother has no effect on the permissibility of marriage for the rest of the siblings.