All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His Slave and Messenger.
We previously highlighted that it is disliked for the husband to suckle and drink milk from his wife's breasts and that some of the scholars held that such an act renders the wife unlawful to the husband. Please refer to fataawa 81931 and 84646.
Therefore, the husband should not suckle or drink milk from his wife's breasts even if for treatment purposes unless there is a guaranteed benefit gained as is the case when there are no other possible means for treatment besides that.
Allaah Knows best.