I looked into this at more than one occasion, because Milwaukee has such an old housing stock, everything is 60-120 years old.Most of the new apartments we see are 4 and 5 star developments with very high rents, this allows to offset the high cost of construction a little better.

As others have said, the best thing your son can do is run far from this deal, buckle down, save his pennies (he probably already is doing this), house-hack, and improve a property with sweat, hard work, developing a DIY skillset, and self-managing tenants. 

OK being a life long CA and selling and developing land here for 50 years..

After analyzing hundreds or even thousands of deals, you develop an intuitive understanding of not just the numbers but their sensitivity.

I'm trying to understand how they collect data so as to develop the best comping practices.

Too many people are sleeping on this.Kentucky Economic Development has many site ready properties in smaller areas that are ripe for rentals. 

I use a spreadsheet I developed to determine my entry costs, carrying costs, cash flow, tax write offs, appreciation and exit costs.

Plus, you get huge appreciation here based on how many companies are moving and developing here! 

This reduces exit options and affects the value. 10) Small number of small units is the most expensive residential development there is.

@Frankie Paterno In most places you will likely find that your $1.2MM will go much further with existing built as opposed to developing.