Many wealth management firms offer this as an extension of their services for high net worth clients (you pay usually but its in-house counsel) who store a lot of money with them, and in some areas you can't kick a rock without finding a trust and estates attorney and wealth management firms.

You are rocking it out, congrats!

The factors here are several layers deep...1- The threshold decision is rooted in local ordinance and zoning...if you're in an area with tight local ordinances you're fighting with the people that live in the neighborhood before you ever reach the city zoning folks...this can go one of many ways2- ROI on the conversion...you're first stop should be with a local architect...they are worth their weight in gold when navigating a project like this and will wade through the regulatory waters much better than you...and a simple phone call may be telling to whether the conversion would be permissible.The extension of this is the cost of the renovation in relationship to the rents received...the stars would really have to align to say you should spend a significant amount of cash to convert a performing building with 4 revenue streams to serve another function (but there is more to this)...and the cost of construction (and lumber in particular) is 5 fold what it was 1.5 years ago...3- As you indicated...exit...I think the only rational reason to convert a 4-unit would be to get condo status or single family/ shared wall and sell one or both of the units to an end buyer (you are basically paying the role of a speculative developer here)...this is happening frequently in locations like Olde Towne East and Merion Village...hard to demonstrate how successful this has been, but it seems far fetched reasonable consumers would pay the same for a  free-standing SFR they would for half of a "duplex" or condo, but who knows for sure.Either way you look at it you're in a residential appraisal situation on the comparable sales approach....4 unit buildings are still "single family" homes. 

My name is Josh Bowser and I am from Slippery Rock, PA but currently living/working in Central KY!

You say he hasn't technically done anything illegal or physical in the house so sending to court or rocking the boat is probably not in anyone's best interest. 

Dupont middle school/ North Star elementary zone there. 

Dupont middle school/ North Star elementary zone there.

Dupont middle school/ North Star elementary zone there.

If roof has rocks that need to be sucked off first and not just a layer but down to decking could cost even more.

I live and work in Rock County, Wisconsin.