Since yours is a second hand report, one can only guess how severe the situation was for the cabin crew. Maybe they were able to fullfill their durty in the galleys or even entirely after some time out.
If, however, the number of cabin crew able for duty was indeed reduced to the number you specified, I should have expected the flight to divert to the nearest suitable airport for medical assistance and maybe crew replacement.
The decision of the commander, though, always depends on the information he/she has available...