+1

I have had a few jobs over the years, that I knew I should have declined and didn't. I payed dearly for it. At the end of the nightmare job, I ran the numbers and found:
1) I made no money from anything I sold because replacements, extra stuff, etc. took all profit (and maybe even a little extra out of my pocket).
2) My final $ per hour I made was less than minimum wage.

When you look back on a job like that, where the customer has dragged you over the coals, you kick yourself and realize it would have been better just to have sit at home and watch TV - at least then you could maybe have had some enjoyment from the time.

Once you are in a job like that, it may still be better to just drop it and walk away. Customer is going to bad mouth you no matter what anyway (just as he has done all the others). No point in losing more time & money trying to please an impossible customer.

[edit]: You also learn how to deal with customers like this, by charging upfront and charging for everything (payments as things occur). It is the same as my last paragraph, except the customer fires you instead of you having to walk away mid-job. Usually happens after they have had to write a few checks, every time they changed something or problems they caused arise. And you refuse to come out when they haven't written the latest check.
The + to this is you are getting paid still to deal with the crap.

3p, I agree and will take it onboard, I'm pretty good at reading people, I was a cop in a former life, and I don't think it was that, like I said the first install of the camera system was smooth as silk, and for the most part the system was fine, except for the heavy volume finger, he's not mad, yet and I think I can deal with him, when he's not been in "Grandpa's cough medicine", plus I was trying to get in good with the GC, but I have scuttled that idea..

I would try to find out how loud he wants it to play- it may not be possible with one set of the existing speakers, regardless of the power amp's output.

There is something else to look at here, which has nothing to do with how loud it actually plays but the customer's mental state when it comes to audio.

This is rare but follow me on this:
There are certain people in this world that to them loud = painful. They want the sound to distort, to them that is loud and how it should sound. They are not happy and will not concede something is loud, unless it is distorting. To them, this sounds good.
I don't know what is wrong with these type of people. Like I said, I think it's a mental thing. But these people do exist and are out there.

This will sound odd but to make them happy, you will have to use speakers that can tolerate a high continuous thermal wattage (not RMS) and use an amp that is below this mark. Then overdrive the amps so you can get an early clipping (distortion) to happen. Now when they crank it up, it will hurt your ears but shouldn't blow the speakers.
I have only ever seen this condition in males. And being most females are more sensitive to distortion and loud sounds, the lady of the house will almost certainly HATE it (as she should).
Note: I would never do something like this. The customer can deal with their own mental problems.

I have heard people conflate loud with clean- it was loud, but definitely not clean at the time. Most people wouldn't know when a system is clipping if they had a gun to their heads, so it's probably useless to even tell them, just limit the system's output and tell them "This is as loud as it goes. If it's not enough, we can't use this equipment".

A few women do like loud, know when it's clean and actually wok in this industry, but they're a tiny minority. This can be an ego-driven attempt to feel good, but it's certainly not necessary and it WILL damage hearing.

In my opinion we are conditioned to equate "loud" with distorted. In my college apartment we could play at levels that made verbal communication difficult, but it was clean. I kept receiving (yelled) requests to "turn it up." With the same group of listeners in a different venue, playing a little nonsense box at distress levels, we had no difficulty with verbal communication and no requests to "turn it up."

At one point I followed up at a customer site after numerous complaints of "not loud enough". On walking in I was stunned at the level they were running. I didn't think that the system could do that -- and it was clean. It was impressive. Yet, the owner (hoarsely) yelled in my ear, "see, that's all the louder it gets." I explained what was happening and quickly left because I didn't have my ear protectors with me, but I don't think that I satisfied his complaint. If this had been a business, OSHA would have shut him down.

In order to resolve issues such as this, I'm often tempted to insert a little diode function generator in the signal path in order to create some distortion at high levels. Of course we know that this is a form of limiter, but I want to put a rough edge on it. I think that this would satisfy the habitual "not loud enough" listeners -- at a safe level. (but they would hate me if they ever figured out how that tiny little circuit fit into the scheme of things)