From this archive of a GQ article here:

But things would get worse. Around 9A.M., on November 21, 1980, Henley called the L.A. Fire Department, seeking medical aid for someone at his home who appeared to he having a seizure. That someone was a prostitute, who turned out to be suffering from aftereffects of Quaaludes and cocaine and who also turned out to be 16 years old. Hours later that day, police came to Henley’s home and arrested him, after reportedly finding quantities of cocaine and mari­juana in the house.

The interesting part about that whole event is that he claimed that the girl was a prostitute. As if the Eagles (who had been a top band for years) would need to call a madam and order up a prostitute, instead of just using the large pool of underage groupies that were common at the time. If Henley himself didn't know of any girls like that, you can be darned sure that the roadies did.