Are there any alternatives to the 1031 exchange he can utilize to prevent paying capital gains taxes? 

I prevent this by building a automatic 3% increase into my leases at renewal.

What can you do to prevent water vapor from traveling from the shower into other rooms and causing mold in the bathrooms or rooms around the bathroom?

Concrete foundation, asphalt/shingle roof, that's all I have.  

Do preventative maintenance on appliances and air conditioners.

In some states the real estate license laws prevent this (as a sort of Buyer Inducement) while others say "induce away."

We recently received a picture that there are large icicles extending from the roof, and I am trying to figure out the most feasible and preventative way to remove the icicles and ice underneath.

It will be inexpensive, keep your good tenant happy and possibly prevent an infestation.

So to save time and prevent it from going into foreclosure I would like to take the property via a sub-2 agreement.

A lot of units were damaged within the condo complex and prevented all owners from renting them out for 6 months.