He needs a good aviation attorney
As with most accidents involving poor judgment, the Feds will definitely charge the pilot with-
FAR Pt. 91.13; "Careless or Reckless Operation":
(a) Aircraft operations for the purpose of air navigation. No person may operate an aircraft in a careless or reckless manner so as to endanger the life or property of another.
For good measure maybe:
Pt. 91.103; "Preflight Action" for not becoming familiar with all information concerning the flight, specifically the presence of obstructions.
&
Pt. 91.119; "Minimum Safe Altitudes" for creating a hazard to property on the ground.
Also, it is likely that they were operating in violation of the company Operations Manual which since approved by the FAA, must be complied with. So possibly more charges for violating:
Pt. 119.5; "Certifications, Authorizations, and Prohibitions."