Oils don't moisturize nappy hair.
Many Mocha Moms remember sitting on the floor between an older woman's knees to have their scalp greased and hair oiled. We've all made the mistake of trying to moisturize nappy hair with grease and oil. Some naps thrive anyway, but I never experienced optimal nappy hair until I began to moisturize with water.
The hair shaft is full of tiny openings. When applied to dry hair, greases, and oils coat the shaft and seal the openings. This prevents the absorption of water. Water makes the nappy hair shaft moist and supple. Oil can make it outwardly greasy, crispy and brittle over time.
Grease and oils play an important part in the moisture process. They lock in moisture. While nappy hair loves water, it evaporates from the shaft quickly. Moisture is balanced when we are able to trap small amounts of water in the shaft before it evaporates. This is achieved by applying oil to damp or wet hair.
Some oils are thicker and heavier than others, leaving a thicker layer on the shaft than others. I've read cautions in numerous places discouraging the use of mineral oil because of its tendency to be drying. I've also read a few testimonies of its effectiveness in moisture regimens. I wonder if the success stories may be attributed to using mineral oil on damp or wet hair. Personally, I prefer to use one pure oil at a time and avoid butter and grease formulations with mineral oil. You will have to experiment to find what works best for your daughter's hair. Stop using anything resulting in crisp and crunchy hair.
We can increase moisture to the hair shaft by adding a creamy water based product like leave in conditioner to damp, or wet hair. As a final step we seal this extra moisture in with an oil or oil based hair butter formulation. Experiment until you find one your daughter's hair likes.
I alternate in applying the following oils to my daughter's damp hair:
100% Unrefined Coconut Oil
100% Unrefined Shea Butter
There are many oils you can try in addition to the above. You can even scent your oils with essential oils which promote good health. Be sure to research the effect of essential oils well before adding them to your hair products.