u/ExcitingSympathy5541

We put a bid on a flipped house. Need advice on this chimney. It’s an old house and there isn’t a fireplace so this seems to be the exhaust for water heater/furnace. We are in negotiations with the seller and they aren’t budging. Explain to me like I’m 10 how this can be fixed and how much. Prefer to tear out and install something more modern. Also, tell me what’s wrong with this. Thank you!