My son has 3a curls as well. I use L'Oriel's new Curl lines Cleansing Conditioner on him as well as my daughter who has 2a hair. It doesn't work on me, but I'm still growing out damaged hair.
His curls last longer before they go into a frizz mat on the back of his head (top always fine). But I also use Shea Moisture Curl Milk as a leave in for him on wash day (3-4 days).
At 22 mos his hair when straight is already 5" long and his curls stand 1-2".
3B - Fine/Norm - Norm Elas/Por - Protein friendly?
Weekly Low-Poo: SM Coconut & Hibiscus Curl & Shine Shampoo
Rinse-Out: Suave Naturals Rosemary Mint
Leave-In: SM Coconut & Hibiscus Curl and Style Milk - Giovanni Light Leave In*
Style: Curls Goddess Curl Gel* SM Coconut & Hibiscus Souffle*
For my Curly Babies:
CoWash: L`Oreal Paris Hydracharge Cleansing Conditioner
* Currently Testing