What is the ruling on a man marrying the daughter of his second wife, knowing that his first wife breastfed this man, and is it a condition for prohibitive breastfeeding that there be five satiating breastfeeds?

If a woman breastfeeds a child five times or more, the child becomes her son and her husband's son through suckling (rada'ah), and a brother to all their children. For suckling to be a prohibitory factor (muharram), it is stipulated that there must be five or more sucklings, and that this occurs within the first two years of the child's life. A suckling (rada'ah) is defined as the child grasping the breast, drinking milk, and then letting go. If there is doubt about the number of sucklings and it is not certain that five sucklings occurred, then the prohibition is not established, because the default is the absence of prohibition. However, if it is certain that five sucklings occurred, then separation between the spouses is obligatory if the wife is the suckled child, because she is not lawful for him.