Source: Fatawa Aman Puri by Sheikh Ghulam Mustafa Zaheer Aman Puri
Question:
What is the correct duration of breastfeeding, and can there be any increase or decrease in this duration?
Answer:
The complete duration of breastfeeding is two years. During this period, if a child has consumed the milk of a woman at least five times, then the prohibition of breastfeeding is established. If after this period a child consumes the milk of a woman, no matter how many times, the prohibition of breastfeeding will not be established.
❀ The command of Allah Almighty is:
﴿وَالْوَالِدَاتُ يُرْضِعْنَ أَوْلَادَهُنَّ حَوْلَيْنِ كَامِلَيْنِ لِمَنْ أَرَادَ أَنْ يُتِمَّ الرَّضَاعَةَ﴾
Reference: (Al-Baqarah: 233)
“Mothers may breastfeed their children for two complete years, for those who wish to complete the nursing (period).”
The final duration for the prohibition of breastfeeding is two years; this does not mean that after this period a child cannot drink a woman's milk. Therefore, if the child is physically weak and cannot consume any food other than the mother's milk, then he can be breastfed for more than two years, but after two years, the breastfeeding will not be established.