All of the duct work etc has been ran. 

Of course, to replace means you probably need to install new furnaces and duct work in addition to all of the patching and soffit work that will require. 

Looking in the crawl space the duct work seems to be fairly new and the plumbing looks good from a quick look under the sinks. 

Brush up on building code requirements: in basements you're looking for egress windows that are 5.7 sq feet or more openable (3ft by 3ft casement style windows work best), and ceiling heights 6ft 8 inches or greater (as little as 6 ft 4 inches is ok under ductwork and beams though)Sounds like your basement would be a home-run to generate some extra rental income - Happy to talk through the details of that strategy with you, just shoot me a DM! 

It's a 40 year old property, so the duct work, electrical, plumbing is outdated and weird, and I'll have to make the windows larger to be up to code for a bedroom -including cutting through the concrete and digging bigger window wells. 

Brush up on building code requirements: in basements you're looking for egress windows that are 5.7 sq feet or more openable (3ft by 3ft casement style windows work best), and ceiling heights 6ft 8 inches or greater (as little as 6 ft 4 inches is ok under ductwork and beams though)2.

Brush up on building code requirements: in basements you're looking for egress windows that are 5.7 sq feet or more openable (3ft by 3ft casement style windows work best), and ceiling heights 6ft 8 inches or greater (as little as 6 ft 4 inches is ok under ductwork and beams though)2.

Best thing that I have done is to charge a monthly pet fee and then put in lots on language in the lease stating that they have to have the ductwork and any carpets professionally cleaned at the end of the lease showing a receipt from a 3rd party explaining the next tenant may be allergic to pets.

In Austin people were mentioning pricing similar to what you listed and they were not sure it was a complete system.And this excluded finishes.That being said, if you are adding a complete system, make sure you locate vents and ductwork.  

It would cost too much to do what he needs to do to get Power of Attorney or Guardianship and even then he is not guaranteed to be able to refinance so he can put in new HVAC duct work.