If you are sure it hasn't been treated with chemicals a bit of grass won't hurt him. It might make him vomit which is normal.
There is some debate as to why they eat it. I've read they eat it because it helps with digestion, they could have a vitamin defiency, to help them vomit or they just like it. No one really knows exactly why.
If you are worried about it, you could offer him some green vegetables instead. That might stop it.
The cat poop
can hurt him if the cat has something (certain types of worms or giardia for example) so make sure he doesn't get that again.
Welcome to YT.
