I also sprayed it on my peach tree because of leaf curl the year before, and I ate every peach this year. If he was spraying it on something he probably considered edible, I would assume it would be fine landing on an area where edible things will grow.

Think of it as free fertilizer. Basically that's what a small dose amounts to.

Agree, you have no concerns, but he may spray other stuff, you might want to mention to him to try and be more careful, like not spraying on windy days!

Copper btw can be used on veggies for various fungi, and yes it is a needed trace element for your plants. They need copper because it speeds up respiration and photosynthesis
Without copper the plant would have stunted growth and the leaves would
be lim (e.g they wouldn't stand and face the sun like usual).

The main problem with copper is if a lot is used over many years it can build up in the soil and that is not good for soil life. A small amount should not matter.

Thank you all for your input. Good to know this isn't an issue. Just glad it was an innocuous substance raining down from over the fence.

To add a small bit of alternate opinion, the following is a link

copper spray fact sheet

In a nutshell, it does have some negative affects, small, but enough that we should acknowledge them.

According to this fact sheet (put out by ncsu.edu ) It stays on leaves for at least 1 to 2 weeks unless washed off by rain or irrigation, therefor, I would wash my produce before I ate it. It has been shown to cause some health problems for humans and is toxic to fish. At normal application rates they say it maybe poisonous to sheep and chickens and Bordeaux is endangering bees.

I note the word "maybe" in relation to sheep and chickens, and also the liver damage they discuss in humans was to vineyard sprayers that, I assume, were exposed to larger doses. Still, it should be used with caution.

If ,as you say, it was "raining down" over the fence, the paper also states that it is readily absorbed thru the skin and this can cause the same symptoms of poisoning as ingesting it.

I suggest, that since no vegetables are in the garden yet, it will be fine. But I would definitely watch when and what he sprays in future.