Curly sue.....

Hi mums out there...
Anyone can advise me how to maintain my 5 year old curly tangles .....
I try and use as much conditioner as I can but her hair still ends up dry and frizzy once its dry.
Its a nightmare to do her hair as she cries a lot cause its soo tangled and I do use the detangling spray....
Maybe I am using the wrong shampoo and conditioner
And worse is when we straighten our hair as I have very fine hair and so does her sis its easy for us, but I spend hours trying to do hers and it still frizzes up.
Maybe I am doing something wrong....maybe I am supposed to put hair food on before or after.....
Please help.