Its not necessarily the FEEDING, its the cats using his backyard as a bathroom because she is feeding them that is the issue.
Will she come over and pick up all the cat crap? Its her direct actions causing this.
It may be time for him to buy some Kitty Kandy and leaving them some specially seasoned After Dinner Mints in his yard, since they have decided to repeatedly invade and vacate their kitty bowels on his property.
The cats are likely not the ones crapping on the grass because they need to bury their scat.
We’ve got a number of felines who were using my flower bed for a litter box and I solved the problem easily.
Included some marigolds, which cats dislike.
And put a couple of boxes of clear plastic forks to good use in the clear spots in the flower bed.
Take the fork, slide the handle into the dirt so that the tines stick up. And use a lot of them.
You won’t see the forks, especially after your plants are established. And after the kitties get their prats poked, they get the idea to jog on.
I haven’t had a problem since I started doing that.