Kittens bite, it is part of their growing up process. You keep your hands away from a kitten that bites. You don't move your fingers under your bedspread or wiggle your feet. This just encourages them to bite you. They are smart, they figure out that your feet and fingers are attached to your hands and they have to bite you.
Play with him with peacoc feathers, or pheasant feathers. If he bites you because you are restraining him by holding him, let him go. If he grabs you with his teeth, don't get mad at him. Just push gently into his mouth, don't pull away, he will only latch on harder.
Your friend's kitten, I would guess has been punished for biting, thus making him into a mean kitty. Cats do not remember good stuff, but they never forget the bad. Treat your kitten with great kindness, he is a tiny creature dependent on you for EVERYTHING don't let him down.