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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Allaah The Exalted Clarified men’s Mahrams, whether from blood relations, nursing relations or marriage relations in His Noble Quran. In fact, if this man is not from among your Mahram-men for one of these reasons, then it is impermissible for you to expose your adornment before him, just like any other non-Mahram man. Moreover, the fact that this man raised you or that he is an old man is not a valid reason under Sharee‘ah for you to expose your adornment before him. In fact, if you did so, you would be held guilty.
Allaah Knows best.