Don't be ridiculous. This website isn't in any legal obligation or risk by making estimates, regardless of how accurate the description of the items is. The estimates have absolutely no relevance or clout no matter how perfect the description is. There is no legally binding aspect of this forum. I was assuming the cymbals were era-current, Avedis Zildjian and Meinl. That's a big jump. The estimate on the stands is based on research I just did, there's an ended auction of stands that sold for $180, for 2 stands. Add shipping and you have $100 a piece. I have seen these go for higher. Most would go for $50. But with replacement value you have to go with retail value. That is how much you should expect to pay to get them replaced. You have to assume the condition of the drums before the water damage is perfect.
But I guess I need to make a disclaimer--I am not in any way a spokesperson for this website.. blah blah blah..
He needs to have them appraised by a professional who is paid to do research and states a valuation that can then be used independently by himself and the insurance company as being agreed upon as being the replacement value. It is almost impossible for that to happen on this website. You can only sight a couple of eBay or craigslist transactions and even then you may or may not have a degree of accuracy, so there are inaccuracies all over the place, beginning with myself, I know what I know and I know I'm not perfect, and have sold certain items to certain people for certain amounts, but I don't claim to be an expert going any further than to follow my own advice based on past experience which is probably about even to some, less than a few, and more than many on drums and cymbals and other musical gear.
But every time someone comments on monetary value of something they have to qualify their statements with the fact that this is just observing past sales, and tendencies. And no one knows what the drums looked like before they got wet, except for this guy. Without that little tidbit of info, I think I can completely agree with the general statements that you can't ascertain a value.