Kind of Important Question here, does Carys leave you if your Morale get to low?
i know you can only recruit her if your morale is abobe 20 but does she leave you or so if your morale drops below a certain point or does she stay either way?
There are 2 morality checks for Carys.
The first check is her entry check, done during her second quest. Her quests themselves could be done regardless, its the outcome of the second ("A cure for Seren", when you help both sisters) that has rather complex morality check. To quote the guide:
Recruit Carys: she will go with her dad if your corruption flags are 2 or more. A flag is gained by each companion with 5+ CP or if the player has morality below 5, if the morality 5 or more a flag decrease instead.
So, you must have at least some positive morale and not be surrounded by perverts and cutthroats. If you can have like 1 corrupted character or have bad morality but good companions, she can join you. If you have bad morality and a corrupted companion or several corrupted companions, she won't join you.
Second check is her leave check. If you have -6 morality, she'll give you a warning. If you have -12, she and Seren will leave the Castle.
P.S. Anyway, here is the guide. A bit off at times (it states it is for 5.8B, but it has some up-to date info while also missing some older info) but the best we have, I think. Hope it'll help you.