السلام عليكم ورحمة الله وبركاته May Allah preserve you Ustadh and grant you Jannatul Furdaus! While I am fasting (nafilah), is it halal for me to cook food for my family (my parents and/or siblings in my case)? JazakAllahu khairan!

Ustadh AbdulAziz al-Haqqan

Yes, it is. Even if you are fasting in Ramadan (the mandatory fasts), the same ruling applies.