Does adopting a child render it Mahram to the adopting woman?

Q: I would like to ask Your Eminence concerning the ruling on a child, who was taken by a couple, when he was two months or less, from an orphanage to raise him as their own, because they had no children and they were old. After a period of time the husband died and the wife has been living alone with the child, cherishing and loving him as a mother would do with her own son. She has asked me to send you a question about the ruling on her relation with the child, as he grows older. Is he considered her Mahram (an unmarriageable relative), or should she observe Hijab (veil) in his presence, because it has come to her knowledge that he is not a Mahram for her? She feels great attachment to this child, as she has brought him up as her own son, and he calls her (Part No. 21; Page No. 50) as any child would call his mother. She says that she tried to breast-feed him when he was an infant, but her breasts discharged no milk. Now, the child is about four or five years of age. She feels confused about him, because she is greatly inclined to him as her own child. I hope Your Eminence would give a sufficient answer in this regard. Is he a Mahram for her? Please bear in mind that he has had no share in the inheritance of her deceased husband according to the Shar`y (Islamically lawful) rulings. The mother asks whether this child is a Mahram for her like her son and, thus, she does not need to observe Hijab in his presence or not.

A: The child taken by the husband and his wife is a stranger to them and has no ties with them, whether on account of consanguinity, marriage, or any other relationship. Since the woman did not breast-feed the child when he was still an infant, she is obligated to observe Hijab when this child becomes of age. She is rewarded for raising, adopting, and sustaining him. We hope that Allah (Exalted be He) would multiply her reward.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.