Is it permissible for the maternal uncle of my father or my mother to shake hands with my daughters without wearing Hijab (veil)?
Is it permissible for my father's maternal uncle to shake hands with my sisters when he visits us?
It is permissible for the daughters of the sister's son to shake hands with their father's maternal uncle because he is one of their Mahrams (unmarriageable relative). The same applies to the mother's maternal uncle. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.