ANSWER:

Yes women must be properly covered from head to toe so that no non mahram man can see the shape of their body or the texture and color of their hair. There should be no free mixing between you and your female cousins and you have no business talking to her as you are non mahram to her! It is not your job to advise her and family gatherings should be segregated.

Is it true that a woman should be concealed so much so that even her cousins that are non mahram should not know her hair colour and how her hair is like? Curly, silky, smooth? Is it permissible to let a bit of hair come out of her hijab? And what should I do about my cousins wife who doesnt wear proper hijab? Tell her or the husband politely?