According to Deborah R. Lilly, author of Wavy, Curly, Kinky: The African-American Child’s Hair Care Guide, your child’s hair is developing between birth and 4 years old. That means that your child’s hair texture can completely change during these years. So with that, be gentle with their hair and don’t over obsess with trying to “train” their hair to be more like yours.
This goes without saying but still needs to be said: DO NOT RELAX your child’s hair before the age of 12. With regards to the blow drying and straightening combo, it’s best to wait until their hair has fully developed, after 4 years old, and only do it sparingly. Heat damage is real and constantly straightening it can cause a child to lose their natural curl pattern. On the other end of that, over brushing or combing your child’s hair can be detrimental to their hair follicle. A parent trying to brush their child’s kinky hair into curls is not going to do anything but cause hair loss. Put the brush and fine tooth comb down, try sticking to wide tooth combs and only use after properly detangling hair.
With that said, one of the best things that a parent can do to make their child’s hair more manageable, regardless of their child’s texture or density of hair, is to properly detangle their hair (and that goes for your own hair as well). A good detangling job prior to washing the hair will help to make hair more manageable post. Detangle by sectioning the hair and then spritzing the hair with water. Gently pull tangles apart by hand, then braid or twist each section once you finish detangling it. If you wash hair with braids in tact, I promise it will go a long way. Co-washing (washing hair with conditioner) is good, so it helps to minimize how often you shampoo to just when you need to cleanse your child’s hair of excess residue/buildup.