Does my grandfather's cousin's daughter have to wear the hijab in the presence of me?

Question

Is it necessary for my grandfather's cousin's daughter to wear the head-cover in front of me?

Answer 1

Yes, it is obligatory for her to observe the Islamic hijab in your presence since you are not her mahram.

Answer 2

Yes.

The Quran commands women to observe hijab from men, other than mahrams, and your relationship is not listed among the mahrams:

وقل للمؤمنات يغضضن من أبصارهن ويحفظن فروجهن ولا يبدين زينتهن إلا ما ظهر منها وليضربن بخمرهن على جيوبهن ولا يبدين زينتهن إلا لبعولتهن أو آبائهن أو آباء بعولتهن أو أبنائهن أو أبناء بعولتهن أو إخوانهن أو بني إخوانهن أو بني أخواتهن أو نسائهن أو ما ملكت أيمانهن أو التابعين غير أولي الإربة من الرجال أو الطفل الذين لم يظهروا على عورات النساء ولا يضربن بأرجلهن ليعلم ما يخفين من زينتهن وتوبوا إلى الله جميعا أيه المؤمنون لعلكم تفلحون

And tell the believing women to reduce [some] of their vision and guard their private parts and not expose their adornment except that which [necessarily] appears thereof and to wrap [a portion of] their headcovers over their chests and not expose their adornment except to their husbands, their fathers, their husbands' fathers, their sons, their husbands' sons, their brothers, their brothers' sons, their sisters' sons, their women, that which their right hands possess, or those male attendants having no physical desire, or children who are not yet aware of the private aspects of women. And let them not stamp their feet to make known what they conceal of their adornment. And turn to Allah in repentance, all of you, O believers, that you might succeed.

^{— Quran 24:31}

Answer 3

Should my grandfather's cousin wear hijab in my presence? Yes, hijab is obligatory on him because he is not a mahram to you.