EC 261/2004 does not apply as AC is not an EU carrier and this is a service to, not from. the EU.
If it did apply, the carrier would have a "duty of care" no matter the reason for the delay/cancellation. While EC 261/2004 does not specify an amount for a 24-hour delay, CAD 22 would not likely be reasonable. But, as AC had no obligation at all, the hotel and CAD 22, are all she will see from AC.
It does not sound as though you proposed any other specific reroute. Perhaps had your wife (not you) done so, she might have received that. It is often the case that carriers will do what is asked if something is proposed. Harried agents at the airport will often do what is asked when presented with the exact flight numbers.
Similarly, if this were a flight xEU, there is nothing in EC 261/2004 which would require AC to reroute onto another carrier. Thus, with the exception of the difference between CAD 22 and what might be more reasonable, there really isn't any difference between what your wife would expect to/from the EU.
A more fruitful avenue here would be for your wife to claim against her travel interruption insurance.