Water damage from years of missing roof cap

[Judd Campbell]

I bought 5 townhomes a few months back and just recently got a 28 foot extension ladder.  one of my guys went up on the roof to clean out the gutters.  My roofs are good to go and the gutters are now clean.  Since these are townhomes with shared walls it concerns me greatly that an adjacent property is missing it's roof cap.  The wood is weathered badly on the trusses and I don't see how the tenant in there is not swimming.  When we put new flooring in the second floor of my unit we noticed some water damage near the shared wall.  not bad but it was concerning since that is not an exterior wall and there is no plumbing in the shared wall. 

I looked the owner up on the PVA and he is a slumlord.  no way he will even give this a second thought.  Can a property be condemned for mold / water intrusion? I am guessing the neighbors second floor is a wreck. 

Should I bring this up with the code enforcement?  I don't want his slumlording to become my problem.  or should I just pay to put a cap on it myself so it does not get any worse?