You should write or call the property owner and ask him to put instructions in writing that he chooses his brother John Ivery as his local agent for all purposes, including collection of rent.
If you don't know how to contact the owner, you can try looking up the records at the property appraiser's website. It should list a mailing address for the owner of record.
If you still can't find a way to contact the owner, make an appointment with a local landlord tenant attorney to help you.
You should always pay with personal checks, money orders, or cashier's checks made payable to the owner so that they can't be altered. if you use personal checks, use a pen with permanent ink when you write the checks. Never ever pay in cash.
If you are unsure, see a local real estate lawyer to talk it over.
The lease should say who exactly is the landlord. If his brother is acting as his "agent" meaning acting on his behalf with his knowledge and permission that is fine, but the lease should say that or the landlord should have given you written notice that his person is acting on his behalf.
Keep all your receipts and make copies just in case there is a problem.
Attorney answers to questions are for general purposes only and do not establish an attorney-client relationship