Without getting into a lot of pharmacology, Albuterol has a wide therapeutic index (The ratio between the toxic dose and the therapeutic dose of a drug), meaning that it would take a lot of Albuterol to cause an overdose. I think the important thing here is not that he broke the rules and (technically) the law, but that he saved her from possible death; I think he acted responsibly. I've seen kids die from asthma (when I worked in the hospital); it can happen. As for the dog, since the dog doesn't weigh as much as a human, and thus would need less of a dose, it's not surprising that it had those problems after ingesting a container of Albuterol (increased pulse and tremors are common side effects).
The LD50 is around 250 times the amount you'd get from a normally prescribed metered-dose inhaler. You'd probably die of CO2 poisoning long before you could huff 250 times.
It is "dangerous" because it is delivered by an inhaler; Since the state can't tell the difference between Albuterol and Butyl-nitrate in the inhaler, they'll just ban all inhalers.
It's "dangerous" because it's inconvenient for the bureaucrats ...