Off topic, but your wife might need some help to learn about taking care of black hair. I (very white with straight hair) had to learn how to take care of and braid DD1's hair. I found the book "It's All Good Hair" to be helpful. https://www.amazon.com/Its-All-Good-Hair-Childrens/dp/0060934875/
And leave in conditioner is a wonderful thing. :)
You need to learn about black hair. I found the book "It's All Good Hair" really helpful to learn how to take care of my biracial daughter's hair when she was little. https://www.amazon.com/Its-All-Good-Hair-Childrens/dp/0060934875
Sulfate free shampoo, leave in conditioner, comb from the bottom and work your way up. Also think about putting it in braids so it doesn't get so tangled. Try using the brand Cantu Kids.