https://www.npr.org/sections/money/2010/11/05/131105373/the-...
I still remember an old Planet Money podcast they did covering a Rent or Buy calculator, It didn't allow for the possibility that the value of a house might fall over time. If you put a negative appreciation rate it would spit out an error. Which in the immediate aftermath of 2007 meant the tool was unable to capture reality.
The parent is minimizing a bunch of coats of owning: maintenance, property tax, included utilities, HOAs, and most importantly opportunity cost.