Okay,this is just my opinion.This sounds like it is no where near any structures on your property.Your only concern is that a whipping action MAY cause your power line to come away from your house.That may happen that may not,I believe that is your opinion not an expert's.I would just let him and the city handle it and butt out.If in the future it does come down along with the power line,it would be a pretty simple matter of getting the power line back up.I would keep the E-mails about your concern.There is to much not known here,are you concerned that the city will charge you to put the power lines back up?The E-mail may or may not help you keep from paying if that is the case.
I also believe in private rights.It really bugs me when I hear about all of these local laws that dictate what you can and can not do on your own property.This guy should not need a law telling him what to do,his common sense should come into play.Once again it sounds like the city was called and their expert is telling the home owner that the tree is not a danger and he does not have to remove it.I only said expert,because any city requiring permission to remove trees should have an expert to keep their butts out of trouble. Having said all of that,I think the guy is nuts(if the pictures show the true story)not to remove the tree for his and his family's own safety