Encourage speaking with a therapist. Organizations like RAINN offer hotlines and resources for survivors of drink spiking and assault.
Contact the bar or club management. As seen in similar cases on r/TwoXChromosomes , checking with the venue is vital for identifying suspects or warning other patrons. The Aftermath: Healing Together
The trauma doesn't end when the drug wears off. Victims often feel "disgusting" or violated, even if no further assault occurred.
Validating her experience is the most important step in her recovery.
Stay by their side. Do not let "helpful" strangers take them to the bathroom or "get them air."