It's a state law on the fire hydrant, just park your friends cars in front of his house. It's a public street he can't stop ya. In fact, if he's an ass about it I would make the point of parking in front of his house all the time.
BTW not a good idea to park in front of a hydrant, they will put the hoses through your car if there is a fire. Usuall process is breaking a window to gain entry and opening all the doors and draping the hoses through the car.