This is a good post and some valid points were made. I agree Mr. P would benefit with the help of a 2nd rooster. Deep down I would love to here that Martin or Rico gets to stay. Secretly rooting for Martin but that is me being selfish.
Now, stepping away from my selfish wishes I have to remind myself that 
@Ponypoor is in a difficult position. With this new job that is permanent she is not going to be around every day. Her aging mother will now be the flocks primary caregiver. If we remember last winter while she was away her mom also filled this role. I do not think her mother was too happy about it and is not 100% a chicken person. I get that, there are people who are not, the world needs all people. I think her mom likes Mr P, that is good. When it comes to bringing up a new rooster yes, a older boy and older hens help in raising him right, it actually plays a huge part in it. Another huge factor is stability with the human caretaker. The boys are right smack in the middle of their "idiot" phase, hormones are kicking in or will be if they have not already. This is a nightmare if you either A. do not have experience with a young cockerel, or B, afraid of roosters. What may help and I wonder if this is driving some of the boys bad behavior is so many young cockerels. Before deciding they all need to go I would take this break at home and make the hard decision to pick just one of the boys. See if getting rid of the rest of them allows your keeper to calm down. He is trying to find his place in the flock. Not only does he have to learn Mr P is the boss, he is competing with his brothers all going through the same thing. That right there may be the key to solving some of your issues. You will know then with your next absence if you will be able to have a multi rooster flock.
If it fails, you tried. They key point to remember though is above all else you have Mr. P. You love him, your mom likes him and most importantly is willing to care for the flock with him as a member of it.