Look at the Sales History - it tells you a number of things.
Aside from telling us that it was bought by John Mack in 1992 from Kaye C. Mack, and then sold in 1996 to Kaye Clements (most likely his ex-wife), it was sold in 2013 to 647 Linden, Inc. for $650,000.
Could it be possible that prior to its sale in 2013, SWM formed a corporation 647 Linden, Inc. to protect her assets and possibly take the proceeds from the home's sale out of the estate. It seems like she sold the house for a bargain to 647 Linden Inc. Perhaps she did it to limit what HM would be entitled to. Knowing that the home needed work and that she was moving to the city, perhaps SWM was being savvy by fixing the place up and then having the ultimate proceeds of the house - which is now on the market for $1.7 million - go to a corporation that would fall under corporate law. Perhaps she had more assets than we thought.
http://chicago.blockshopper.com/property/16064140090000/647_linden
I looked up the corporation details with the Illinois Secretary of State - 647 Linden, Inc. only shows a registered agent - who also happens to be an attorney in Oak Park.
http://www.ilsos.gov/corporatellc/CorporateLlcController
Or...I could be totally wrong. All I do know is that Linden Ave. is one of the nicest streets in Oak Park. Regardless of the homes condition, I would have thought the house was worth a lot more than $650,000.