Note many of your items in this project are not related to health and safety.  

He did mention that because of the air quality his health is effected and he will sue me, and how would I like it if my daughter lived in that house with bad air.

Depending on the health of your parents, waiting until a death, although grim, could wipe out significant amounts of capital gains. 

I ended up leaving the partnership due to venturing off to focus on my startup but no bad blood.Recently I’ve been contacted by the father of one of the partners and he’s having some health issues but in the midst of it all the property is having some foundation issues.

When you don't need to bring things up to current code, only perhaps make health and safety updates required for renting.3.

The inspections could include, but are not limited to, building, zoning, VDOT, fire, and health department.

I am purchasing and renovating a house 1 mile from a Mayo Clinic with the intention of making it a STR/MTR. 

Health care beeing the prime example: the american for-profit health care system looks like an unbelievably rigged pyramid scheme designed to extract money from the population - this is so clear when you have the comparison to other countries.

The neighbor bought it with the intention of fixing it up but due to health deterioration was not able to do so.

This step must be done carefully to avoid further damage.Structural Repairs: Address any structural damage first, including the roof, walls, and foundation.Systems Repair: Repair or replace electrical, plumbing, and HVAC systems as needed.Interior Restoration: Once the structural and system repairs are complete, focus on restoring the interior, including insulation, drywall, flooring, and fixtures.Safety and Health Concerns:Air Quality: Ensure proper ventilation and air quality during and after the restoration process to remove smoke odors and contaminants.Mold Remediation: Check for and address any mold growth, which can be a common issue in fire-damaged properties due to water used in firefighting.Final Inspections:City Inspections: Coordinate with the city for final inspections to ensure that the property is safe and habitable.Fire Department Clearance: Obtain clearance from the Fire Department confirming that the property is safe to occupy.I hope this helps, best of luck!