What is the name of your state (only U.S. law)? CA
I help pay toward the rent for my parent. Am I legally entitled to the monthly statement from the management? If I pay another family member who pays the sum, am I still entitled to the statement?
You aren't one the lease, they have no busines relationship with you. As such, they have no obligaiton to provide you with any type of statement.
ex. I work in child support. If Jane Smith brings in a suport payment for her borfiend John Doe, I can take the payment and, say thank you and send it on the the payment center. If she asks for info about the case, I cannot even acknowledge its existence, even though she just made a payment on it.