Milan would find more to work on with Doc besides his aggressive territorial make-up. Since we found him -- the runt of a litter and not marked correctly for registration -- Doc has had issues. He's nervous. When he gets more than "usually nervous," he finds something to mark.* He cannot be persuaded to do anything he doesn't want to do, even with the threat of mild, ah, correction. One technique for gently correcting cats is a spray bottle filled with water. A cat jumps on a counter? Spritz the cat. Two or three times, and the cat will learn to jump on the counters only when the human is not present.**
Try that with Doc, and he will simply creep into a corner or under a bed (or anywhere I cannot reach him from my wheelchair) and allow me to give him a bath with the spritz bottle.
Doc has other phobias, one of which exacerbates the current rock-throwing neighbor situation. Doc has developed a fear of our back yard. The cause? I do not know. Perhaps he's simply a city-boy, traumatized by the wide-open spaces and innumerable odors. The yard is a picket-fenced area of forty by 100 feet, and he has plenty of things to see and bark at, smell and bark at, but he must be picked up and carried through the patio door. Read the previous notation about corners, beds, and hiding places to understand the problem with that phobia for me.
The solution seems to be evolving toward a new home, and I have taken my computer to craigslist and I'm using the friend-family grapevine. Doc expresses no preferences, although he'd like one last run at the neighbor nemesis before he takes up his new residents.
* My wife swears there will never be another male cat or dog in this house. Female dogs may be dominant enough to become pack-leaders, but at least they are never compelled to spritz-mark their territory.
** What cats do when we are not present has not really happened.