Q: Can a husband drink his wife's breast milk? This cured my Asthma and increased my immunity. The wife is happy to do so.
A: Drinking of the wife's breast milk, although it does not affect the Nikah, is forbidden in the Shari'ah, even if your wife grants permission. It may be a cure for Asthma and an immunity booster, but it would still be forbidden for you. There are many other permissible medications for these purposes, which you can use. (Fataawa Rahimiyyah V2 P112)
And Allah Ta'aala knows best.
Moulana Yusuf Laher
Checked and approved by: Mufti Siraj Desai