My brother and I can both cook very well (I cooked an entire thanksgiving meal including homemade sweet potato pies for all of the black graduates who didn't go home last year). I can't say who's better because we cook different meals. He can grill his ass off, cook a mean steak, and is great at cooking seafood (I really think he should become a chef). Grilling, oxtails, and neck bones are about the about the only thing I haven't learned to do independently (I don't visit home enough to actually learn the technique nor do I normally eat oxtails and neck bones

). We both feed off of each other in terms learning more about cooking and techniques.
My older sister is getting there. She started late in the game and I wouldn't call her a great cook at all. She is decent and her husband and children aren't complaining to my knowledge (she probably just doesn't cook often enough).