Ayon, this is nothing but puppy play bites. You got to teach the puppy her limitation. Am sure she must have been unintentionally encouraged to bite your family members. Don't allow the pup to take your fingers/hands on her mouth. Am sure you or your family member may have allowed her to do so. If she repeates this behaviour then just take your hands off immediately and ignore her. Ignoring means no eye to eye contact. Just behave as if the puppy doesn't exist around you. This way, she'd realise that the biting behaviour is not yeilding good results. The moment she stops, reward her with a good treat. This way she'll be able to understand that biting is a bad habbit. Also, if she tries to bite or does anything wrong, don't say no no loudly because anything loud may make the puppy even more excited to repeat or continue the current action. Just ignore her for a matter of 2 minutes or so and puppy will realise that she's doing wrong.
Secondly, I encourage dog owners to teach puppy different skills. Teach them different things and biting will be forgotten by her. Teach basic commands like sit, stay, come, etc. Spend a lot of time training the puppy. Labradors are wonderful retrievers so make him run after balls and toys. Make him feel tired and he's forget biting as a habbit.
Thirdly, a two month old puppy tends to be very mouth. Teething causes intense pain and irritation which they try to soothe by either chewing our furniture or biting our fingers. Keep raw hide bones around her which she'll chew for a while and then feel tired and sleep.
I don't think you have to panic so much if she has drawn blood but if you want you can get rabbies vaccination done for your brother. Why have you not taken the puppy to vet yet??? By now, a deworming & vaccination schedule should have started.