The first order of business is, is it on his property or the power company easement?
If it is on the easement and a architect/civil engineer did the lot plan and the easement is properly marked they likely share in the liability. It is also the reponsibility of the civil engineer to know the set back requirements, not the home owner.
I used to live in an apartment 30 years ago that was practicallly right underneath some HV Tower power lines. My stereo system of the time (Pioneer/Marantz) had a constant BUZZZZZZZZZZ................