You can take the pit bull dogs' owner to Small Claims court. Please see the link below. First you should send a demand letter with a copy of the vet bills, and if the dogs' owner doesn't pay by the deadline, you should sue.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
Ms. Koslyn provided an excellent answer. You can also hire an attorne who specializes in animal law.
Disclaimer: The following was not legal advice, and cannot be relied on. Time is of the essence. Do not delay.
In CA, a dog owner is strictly liable for any damages caused by his dog biting someone. In other words, you don't need to prove negligence. You just need to prove that the dog bit your friend.
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