If there’s something I learned from years of managing a business is that there is what’s right, and there is what’s good for your business. Sometimes, making small, REASONABLE concessions to clients will earn their loyalty and bring more business, which will ultimately offset the previous loss many times over.
You should consider the following variables:
How reasonable is this concession?
Agreeing to unreasonable concessions may lead to more unreasonable concessions expected by this client. In this case, while the request is not that reasonable, it is very clear that it should be a one-time thing based on real events… at least until the following hurricane.
Are there good chances the client will keep buying from you if you make this concession, and conversely, is there a chance he will take his business elsewhere at some point if you don’t agree to it?
You should consider this only if he’s a repeat customer. Don’t trust someone who just bought from you once and promises ‘a lot of work’ down the line.
Do you NEED this client to keep buying from you?
If you are swamped with work most of the time, letting the client go to make room for less ‘troublesome’ clients may be advisable
Is the amount of work/money you will lose by agreeing to this client’s request something you are willing to forfeit in exchange for the possibility that there is more work for you down the line?
If the amount is too high for the benefits/profit you would obtain in the future, it may be worth losing the client over. More will probably come.
I’m not giving you easy answers because there are none. But these are some points that you should consider for your specific case. None of us know your client and situation better than you do.