Answer:
(Fatwa: 165/150=L/1430)
As far as educating and advising good (Dawah) is concerned, you can do it observing purdah, but it is unlawful to talk to her brazenly and without purdah.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
