Yes. The money in the 529 account is deemed property of the owner and can be used to satisfy debts of the owner.
Ways to approach this. First, open the account in the name of an owner other than the doctor. This could be a spouse, close relative or trust. This entails the risk of a loss of control (from the doctor's perspective) and addional costs if a trust is to be created. Second, some states exempt money from 529 accounts from levy. The problem is that such exemptions will probably not be recognized in other states (IMHO) and aggregious situations will probably provoke a fraudulent transfer lawsuit or a legislative recall of the exemption. Third, buy adequate malpractice insurance and direct the insurance company to settle any claim within the coverage limit.