My daughter is also half white and half African American, her hair is very curly (the large bouncy curls) and tangles easily, when it was longer we struggled to keep it from tangling, because she loved it down. Ran into the same problems you have right now. My sister works with a woman who has a wide array of heritage and her hair posed as a problem for her when she was younger the site she sent me for use on my daughter is http://store.goldenmartbeautysupply.com/motions.html
she swears by the products on here. I have been unable to get any of these as of yet so I don't know how they work, but for my daughter I use Vavoom's Glaze (salon purchase) and John Freida's Play Down ($5.00 Wal Mart). I use them together with her leave in conditioner (pantene for hydrating curls OR Pantene for women of color (great moisturizer!), (overkill I know) BUT the best part is it keeps her curls together without making them feel like she has product in her hair. That is important to me. My aunt owns a salon and says the sleek line of hair products is the best one to use, because it penetrates the hair and it is made specially for people that want tangle free, frizz free, either straight or curly hair, and it is made for the more coarse hair (I tried it but looked like I soaked my head in a vat of oil, yet my daughters hair just looks healthy) I wish you luck trying to find the best products that work with your daughters hair. I would stay away from the cheap hair lotions found at Wal Mart, they just dried out my daughters hair, and caused breakage. If you need more info feel free to contact me.
H.
also, if you comb her hair when it's wet, it will go through easier, and will be easier on the both of you!