As long as he called the local tower with a flight plan he would be okay(I think).
Dean Kamen flies his helicopter from his house in Bedford, NH to downtown Manchester, NH to DECA(his company and building he owns) all the time. He calls into the tower at the Manchester airport prior to departure with his flight plan.
It is less than five miles.
He's not required to contact any tower if he's flying Visual Flight Rules (VFR), which most helicopters do, and not flying in controlled airspace.
I probably would call the tower to not be rude, but unless there is a restricted area a VFR flight is perfectly legal with no plan.