Isn't that just Tenancy-in-Common?

https://www.thetaxadviser.com/issues/2016/nov/fractional-interests-in-property.html

So they each own 50% of the property?  The devil's in the details but you're probably splitting all of Dad's assets into two (50% basis/accum depr) and then selling the new "half".  The old half would continue to depreciate.

Son then places his new "half" of property in service and starts fresh depreciation from the purchase price.

The bigger mess is probably dealing with income/expenses going forward.  I'd punt, but then I don't like volunteering to deal with other people's headaches.