I am not a suer and don't even like the word. It seems that we all do too much of that and everyong now is afraid of doing anything to help a person for fear of being sued.
Roof leaks are the hardest thing to fix on the first try. I have found that I am very careful on my wording and "promises" when attempting to fix a leak. I find that on leaks, I will be back two times at least. What you do is to identify where the leak is and do the necessary work then, and wait for the next rain to see if you got it, got most of it, or missed it completely. I am leary of anyone that can state and fix a leak on the first visit.
Fixing leaks are a big profit drain to me because of the return trips.
Skylights, fireplaces, any area where a hole is made in the roof is going to be at some time a potential leak area.
Now, if I was contracted to fix your leak, I would have initially looked at flashing, the cricket, and the area around the chimney first. I would have makes small improvements in those areas. I would not have hit you up for that huge amount anyway.
Crickett, think of a crickett as a "V" hulled row boat turned upside down and cut in half from midships to midships. Then lay this down with the bow facing up the roof and the cut off section agains the chimney. This crickett acts as a diverter to move the water away from the chimney instead of crashing head on into the chimney and causing great leaps of water up and over the flashing, which then will leak down the chimney and dump out somewhere inside.
Was the crickett taken off and examined for a leak under that?
Sueing: You will spend more time and money in the law suit or attempt to find remedy than you will if you sit down and talk to this person one on one and explain to him, if this was his house and his problem and I was the carpenter what would you want and do?
If he has to stand in the attic and you have to stand on the roof with a garden hose spraying water, then this is what has to be done.