Yeah, and it is kinda weird that he says "I can't do that to Aunt May, after all she's been through" to Ned when convincing him to keep quiet. What about what he's been through?
It really changes the film if you think about the way everyone responds and reacts to him if you also consider that almost all of them would have known that his "dad" was murdered probably no more than a year ago. I mean, it makes Flash look even worse than he already does, but it would explain why everyone at the school is willing to accept his at times unreliable and otherwise irresponsible behavior when he runs off all the time.
At the same time, Aunt May didn't really behave like she's been through a lot. She seemed fairly well adjusted and even chipper.