Yes, it doesn't run every day, but it runs more frequently in the Summer time. There's also one listed for Fridays that goes by way of Antequera.
That's precisely why I referred Silvy to the Eurolines web site.
BTW
She might be able to catch the Luisitania Express (train) at Oriente station, which is much closer to Lisbon's Portela airport and from which it will depart about 15-minutes after Santa Apolonia. It would be a tight squeeze.