Ive never heard of pill hangover, maybe the patient is implying withdrawal symptoms. If it’s something like a narcotic pill, oxycodone and the like, then there are medications to treat the withdrawal.

There are also benzos, antidepressants, and other types of “pills” that produce a kind of withdrawal and all of them would benefit some kind of medical intervention.

Home remedies have their place, but some withdrawal symptoms can be life threatening. Advise this person to go the hospital to be monitored.