It sounds like he'd only been on that route for 4 days. If he was supposed to know all 60 kids, I think he needed to be given more support, such as a written list saying what kids got off at which stop. Else how is he supposed to know? Even if you think he should have memorised the entire sequence by the fourth day, how was he supposed to manage on the first day?

So the school or bus company should have given him a list, but they didn't. Presumably because it's not actually his job. Since the kid was travelling alone, he could reasonably suppose it was competent to do so.

In my opinion it is unfair of the parents to assume other people will look after their children for them.