These lawsuits always bother me, don't tea and coffee usually involve hot water? is it not common sense that hot water can burn? Is there not a responsibility for individual, it is not like the FA was providing service with malice!
There's hot and then there's
scalding hot and the temperature and it being served without a lid seem to be the basis of the lawsuit.
BTW while the passenger may be from YEG the flight surely wasn't as there are no nonstop AC mainline flights from here to SFO.