I'm not a fan of AC, and the service failure was pretty bad, but, with the exception of somehow not actually booking the guy on the first flight out when they told him he would be (a significant failure), AC at least held to their duty of care and, though it took three tries, there was an AC employee who treated him like a passenger with a problem not of his own making.
AC should refund his fare and fairly reimburse any ancillary costs he incurred due to their mistakes. Mistakes are made, but recovery is what you judge.
Compared to other reported incidents, this was actually pretty good for AC.