Let's clarify a bit. There's no product that you have to use. If you like using leave-in, that's your deal. It's your hair, so you can use whatever products you like on it...
Anyway, ITA with the other post about cutting off the damaged parts. Also, if your hair is too short to finger comb, I would use a flexible fine/wide tooth comb (depending on whether your hair is fine or coarse or really, just personal preference) to detangle. Make sure to really saturate your hair with conditioner and water first.
And by the way, conditioner and leave-in are not necessarily different things. They're both conditioners, just for different purposes. Really, you can use your Co-wash condish (though I suppose you don't co-wash, but just low-poo) or your RO (rinse out) condish as leave-ins...
I don't know where people got the idea that leaving the conditioner in makes your hair fall out or something ridiculous like that.
Also I'd definitely look into knowing your curl properties rather than curl pattern... (helps a lot with trouble-shooting)
Hair Type: 3c, Med-High Density, Low Porosity
CG since '09
Low Poo: KC Come Clean
Condish: AOHR, TN (Avocado), TJ Balancing Moisture
Leave in: GDL, KBB
Curl Lotion/Gel: CHS/CK
Others: CJ Curl Rehab, Jojoba Oil