Another one I wish I had taken earlier was to get involved with a boutique or specialized commercial broker. 

Calculating these losses involves documenting the fair market value of the property before and after the disaster, adjusted for any insurance or other reimbursements.

I think it speaks volumes regarding your care to the situation the heir is involved in.

I just want to be involved and learn more so I could achieve more eventually.

Then involve a GC once you understand the scope of work.

Understand the fees involved and calculate the total cost for an entire year of management so you can compare the different managers.

As far as the sale of a property with a mortgage on it, that all gets sorted out at close. ie, you bring your money, the bank gets what they have coming, the realtor gets what they have coming (if there's one involved) and the seller gets the rest.

The capital stack especially in CA is VERY complex and typically involves everything and more that you mentioned.

The requirement to do this generally involves an experienced GC signing on the borrowing entity as a 20+% owner thus making them a signatory on the loan and responsible for the debt which in most cases is not very easy to find.

Got insurance involved and use that money to remodel the entire inside, and add a new roof.