It isn't illegal for him to feed the foxes, unless there is a city ordinance there against feeding wildlife. State laws prohibit feeding deer, but not other wildlife. However, like many other things, just because it isn't illegal doesn't mean it's a good idea.
If you have a good relationship with your neighbor, perhaps you can share some of this information with him: For the health and safety of the foxes, feeding them is just a bad idea. It can encourage more animals to an area than the habitat can really support. That sort of situation can lead to the spread of disease. And foxes that lose their fear of people (because they are being fed) can wind up causing problems with the neighbors. That often ends with the fox(es) being trapped and euthanized. Finally, foxes are great hunters. They don't need our help with raising their family. The food people feed them is never as good for them as what they find for themselves naturally.
For the rest of the neighbors, this info is important to know: The foxes will likely be more aggressive towards dogs at this time of year since they are protecting their young. And cat owners should watch out for the cats. But a reminder from a fellow cat owner, cats kill lots of birds and small mammals. Even well fed cats will do that. So indoors is a better place for cats to be.
When the foxes show up in your yard, go out and make loud noises (or spray water towards them with a hose) to make it clear that they aren't welcome on your property. They will get the message.
If you have more questions, please let me know.
