Q: Is there purdah between the husband's baligh son and the wife's baligh daughter from a previous marriage? Would they become milk brothers and sisters if the new wife has a baby from her husband and breast feeds the baby? Will the breast feeding of this mutual brother and sister render his and her children milk siblings. Please explain the ruling according to hanafi and shafi.
A:
They can get married.
No.
No. The children of the wife from the previous nikah will be uterine brothers or sisters of the children born from this marriage. Similarly the children of the husband from the previous nikaah will be the consanguine brothers or sisters of the children born from this marriage.
And Allah Ta'ala (الله تعالى) knows best.
ويجوز أن يتزوج الرجل بأخت أخيه من الرضاع لأنه يجوز أن يتزوج بأخت أخيه من النسب وذلك مثل الأخ من الأب إذا كانت له أخت من أمه جاز لأخيه من أبيه أن يتزوجها (هداية 2/351)