Got a feeling he will try to deduct this from my security deposit since I won't agree to pay for the pipe.

Make sure you get copies of the current leases along with the security deposits and familiarize yourself with the local tenancy laws.For rentals, you may want to look at vinyl plank instead of carpet. 

You also have to perform due diligence for trying to find another tenant.Or you all can come to an agreement (put it in writing) that she pays Dec. rent (whether she lives there or not), allows showings, and you also keep the security deposit. 

However, if you have a truly excellent single older adult, non-smoker, no pets, coming with little to no furniture, and he will be the only occupant, giving you a honking big damage deposit, plus he doesn't mind that you're gonna have it on the market while he's there, with showings, you might consider it. 

If its under deposit, it's under deposit. 

If for some reason I change my mind, or when I see it its way worse than I thought, I cancel, my deposit is refunded before I even start paying for inspections.  

The long term leases lets me get the cash deposit as well, just in case they end up damaging something.  

Or lets say a tenant causes some damage beyond their security deposit.

Bid, win, give deposit, close.

(this would be quite natural since I'd be nearly fuming at that point) Maybe reiterate things like rent, late fees, deposits, early termination,....the things that tenants don't like to hear about.Just an idea.