DD is 14 and has lovely long, wavy hair - but it gets frizzy bits sticking up (worse after the summer). I've got a totally different type of hair so don't know what products would be best suited to tame it - bearing in mind that being a teen it can manage to be a bit greasy at the same time.
I don't know how anyone else uses the coconut oil but I wash their hair then coat in the oil. Use about a teaspoon of it in my hand. Whack on a shower cap and leave ideally overnight but at least an hour or two then wash it off.
Hhm. I'd try combing conditioner through it while wet and then not brushing it once it's dry. Waves and curls look best when they're defined, not fluffy, and the way to do that is to have it clumped together, if you see what I mean. Brushing disturbs that, and, if it isn't in great condition from her sports, it might be breakage.
Curly girl basics : ideally don't shampoo, if you do use an slf free shampoo, instead wash with conditioner. Only comb hair when wet w cpnditinner in. Do not brush comb etc when dry. Use only silicone free products, if you do use a siliconeyou must shampoo thoroughly and start again ( you can go low poo you cannot go low cone). Use a defining product and gel and help curls form by finger curling when damp. You can revive curls by spraying w water to avoid wetting it every day. Try this for 6 weeks - it is a revelation. You will not go back .btw curly hair treated like this and with enough oil to maintain it will look absolutely amazing after contact e salt water so the swimming will make it bette. Believe and check out youtube clips lots of curly girls with great hair and they all do this the products vary the basics are always the same