At a certain point, if Lily Bowen is the active Companion, the Courier may begin to hear a recording of children greeting their grandmother. This signals the start of Lily's unmarked quest. The playback of the recording of her grandchildren occurs when the following conditions are all satisfied:
The Courier has talked to Lily about Leo and replied about it (generally available in her typical dialogue tree asking her about herself)
The Courier witnessed her suffer a psychotic break during combat (health is reduced to about half or below, the Courier can cause her health to be reduced to half or below and does not have to be in combat and it causes the same outcome) and talked with her about it
You have witnessed her taking her medicine and talked to her about it (new dialogue option available in dialogue tree asking her about herself) She says "Medicine Time", "Hush Leo; it's medicine time now" or "Grandma has to take her pills now, Dearie" when she takes her medicine.
To complete the quest, the Courier must listen to the entire recording and then open a dialogue with Lily. After asking her several questions and discovering that she has only been taking half the recommended dosage of her medicine, the Courier is given three choices:
Recommend that Lily begin taking the complete dosage. If this option is chosen, Lily will stop suffering psychotic breaks altogether, but will suffer some permanent combat penalties - these remain in effect regardless of her mental state. (Melee Weapons skill set to 60)
Recommend that Lily continue to take half her dosage. If this option is chosen, she will continue to suffer psychotic breaks when she is reduced to one-quarter HP, but will now calm herself immediately if the player enters Sneak mode.
Recommend that Lily stop taking her medicine altogether. If this option is chosen, Lily will now suffer psychotic breaks when reduced to half HP, but will gain several permanent stat bonuses - these remain in effect regardless of her mental state. (Melee Weapons skill set to 100)
The Courier's choice will also have an effect on which game ending Lily receives.
Some quest stages can be started through the use of console commands:
To start the medicine dialogue, enter set "160267".ftimer to -1 and set "160267".bMedicineTime to 1
To start the holotape dialogue, enter set "160267".fresttimer to 1 and set "160267".bdoonce to 1
To start the psychotic break dialogue, enter set "13e510".bPsychoticBreak to 1. This won't make Lily enter a psychotic break, it will however unlock the dialogue option about it and allow for the quest to proceed normally.