I am very sorry to hear about your daughter. The time within which to start a legal action in New York is goverened by laws called 'Statutes of Limitations'. The Statute of Limitations to sue for malpractice is generally 2 1/2 years from the time the malpractice is alleged to have occurred. However, this time period can be shortened by factors such as whether the doctor/hospital against whom the malpractice is alleged is a municipality or an employee thereof. In such cases, other, shorter time requirements may also apply, such as the time within which to file a notice of claim (90 days). If you are considering legal action, it is best to act quickly and seek the advice of a qualified medical malpractice attorney.
Although I am not licensed in NY, because your daughter may have claims for injuries as a result of any malpractice the statute of limitations for her claims appears to be 10 extended to three years after her eighteenth birthday or no longer than 10 years from the time of the negligence which ever is sooner.
If you are interested in investigation the case I would suggest you contact a lawyer who is experienced in handling medical malpractice cases.
A roundup of the best tips and legal advice.