The breed is not really relevant. At 12 weeks all pups should have had bite inhibition instilled into them by their dam - were these taken from her when they were very young or did they stay with her till your daughter got the pups? Has your daughter spoken to the breeder about the problem - he/she may be willing to take the pup back and either refund or replace it - I would.
Your daughter needs to take the bitch pup on its own and retrain it. I realise this is time consuming but it is that or euthanasia. She must let the pup come to her and if she makes ANY attempt to bite or even mouth her she must give the command no and squeal loudly - as another pup might do. If this doesn't give any improvement in a couple of days then for the peace and safety of the family she needs to talk to the breeder, either rehome it with a non child owner (although even then they can come in contact with other children) if the breeder is no help, or send it away for training to a specialist in behaviour.
ps Cavaliers are not generally known to be aggressive so I suspect it is a bite inhibition problem rather than anything else, in which case it is definitely a retraining issue