What is incumbent upon a mahram if the violation of his female mahrams regarding hijab is minor, such as revealing the eyes and not wearing socks or gloves? And is his silence about that considered forbidden?

A man is a guardian and responsible for his household, and he must prevent his female mahrams from forbidden acts and enjoin them to good, as the Prophet, peace and blessings be upon him, said: "Indeed, all of you are guardians, and all of you are responsible for your charges... And a man is a guardian over the people of his household, and he is responsible for them."

And for a woman to expose her feet and part of her leg is forbidden and must be denounced, whereas it is permissible to expose the eyes out of necessity and to the extent of that necessity, without adornment, while observing the Shariah guidelines for denunciation, such as wisdom, good counsel, and gradualness.