There is no specific law that would cover this issue. However, if the property management company is operated by a real estate broker (which is required, if the property management company "
eases or rents or offers to lease or rent, or places for rent, or solicits listings of places for rent, or solicits for prospective tenants, or negotiates the sale, purchase or exchanges of leases on real property, or on a business
opportunity, or collects rents from real property, or improvements thereon, or from business opportunities." Bus. & Prof. Code 10131(b)), then if your friend's contract is for the purposes of managing your friend's property, then the management company owes a duty of fiduciary and loyalty to your friend, and that duty could be breached if the management company refuses to provide necessary business records to your friend.
A breach of fiduciary/loyalty would give your friend both a common law action for the breach/malpractice, and the right to complain to the Department of Real Estate
Hope this helps.
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