>>881276lol It affects the liver, not appendix. They were fishing for an appendectomy. They love making money off those. Like I said before, unless he ate an entire plant or several plants, he'd be fine. And when not fine, you'd more than likely not even know it since there are no real symptoms. It causes temporary lesions on the liver.
He's more in danger of eating potatoes that might have green skin than from eating a small amount of Ageratum. Still, you always need to research anything very well before eating something you don't know about. It can be life or death, depending on the plant.