The breast milk belongs to the sire
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ جَاءَ عَمِّي مِنَ الرَّضَاعَةِ يَسْتَأْذِنُ عَلَىَّ فَأَبَيْتُ أَنْ آذَنَ لَهُ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " فَلْيَلِجْ عَلَيْكِ عَمُّكِ " . فَقُلْتُ إِنَّمَا أَرْضَعَتْنِي الْمَرْأَةُ وَلَمْ يُرْضِعْنِي الرَّجُلُ . قَالَ " إِنَّهُ عَمُّكِ فَلْيَلِجْ عَلَيْكِ " .
It was narrated that 'Aishah said: X“My paternal uncle through breastfeeding came to visit me and I refused to let him in. The Messenger of Allah (ﷺ) said: 'Let your paternal uncle visit you.' I said: 'But it is the woman who breastfed me; the man did not breastfeed me.' He said: 'He is your paternal uncle; let him visit you.”