Advice caring for blonde curly hair

My 1st child of 7 w/curly hair & I need advice on how to manage it and take care of it. Anytime it's humid or she slightly sweats it turns into the tightest cork screw curls, absolutely adorable!! Otherwise it has gentle soft curls, and this didn't start till she turned 9 months old...

BUT ... She's getting some really bad knots in it lately as it gets curlier and longer. Are there certain shampoos that actually make a difference with curly hair? Myself and my other 6 kids have the absolute straightest hair. My mom has absolutely curly hair tho but didn't have any advice & is a very dark brown, super thick and course compared to my daughters fine thin blonde hair. My happy little blonde curly haired blue eyed beauty 💖💝