Buses are notorious for making people sick, even if they don't get motion sickness! I was talking to my friend who's a teacher, they just went on a field trip and she said like 10 kids said they felt sick on the bus ride but ended up perfectly fine! I for one am traumatized by a bus ride when I was in 5th grade we went on a field trip far (like 2 hours away) and it was a windy 2 lane road and a kid got sick on the way back. The bus didn't stop and we had to ride that whole way back like that OMG. I will never ride a school bus again. I go on my kids field trips but I drive my own car. I don't do the bus thing nope no way no how! Lol! He could have had slight motion sickness or ate something that didn't agree with him. I think you will be just fine! Hugs!