So back to my original translation, what about
A young shepherd brought a tapered ball of dung to help Fabre.
Wait, earlier you said "Fabre didn't do the action.", but I never said that either, I don't understand that comment.
My translation was "A young shepherd helped Fabre [by] bringing a tapered ball of dung [to him]."
You are saying that Fabre wasn't helped by bringing but then you say that the core is 青年が玉を持ってきます which is a young man brings/will bring a ball. So the shepherd did bring a ball.
Thank you for following up on me with this one.