I though Larry heard the conversation, between Carley and Lee, trough the door while suffering from the attack. That's how he knows and why he knows so little about it.
She knew how to treat him, that's why they were in a drug store. The lack of keys didn't let her get the medication in time.
In the novel her father is EVERETT and at some point she will have a bf with a middle name LEE.. put together and what do you get. Hard to say anything else, until next episode comes out.