Hello There! I am a newbie here, so I hope that I am posting this right!

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Who I am: A Real Estate Agent
The Problem: The inspector said that while he was inspecting the Brick Chimney that the bricks on the chimney int he attic are deteriorated and thyere are holes to the flue. As a result this condition may allow carbon monozide to enter the home. (there are detectors in the home) The onloy appliance using the chimney is the water heater and he recommends a power vent be installed on the water heater and the chimney by abandoned prior to closing.
I need to know

the solution: Is this the best suggestion and is it necessary? What is the estimated costs of doing such a project? If this should be done...does anyone know a realiable plumber to handle the project?
Thank you for your time and I owe you some advice in my field now!!