I read either on this board or the Long hair community...that a catnip rinse (1 teaspoon dried catnip soaked into 1 cup boiled water for 30 minutes.) done after shampoo but just before conditionner is practically a miracle against splits. People have tried it with amazing results.
You need to soak the catnip in a container with a lid though, because there are good oils that can evaporate. After the 30 minutes, shake well to collect the oil on the lid and use.
It's also very important to use the catnip tea on clean hair with no residue or conditionner. And not use more then 1 teaspoon for 1 cup ratio because it then gives opposite results.
Free the Curls!