You are describing nit treatment- conditioner, comb.
Nit check is like the nit nurse used to do. DC watching tv, lean over the sofa, give them a hug then part their hair a few times looking for movement. Behind the ears, nape of the neck, and a couple other spots. Look for white empty egg cases. Brown full cases are hard to spot.
If you do it a couple of times a week, you’ll spot them early and treat them fast. Even if you miss them, you will see them before it’s an infestation.
DSis told me lice are huge. Well, yes they are, but only the adults. Whenever I spotted them, it wasn’t the single adult, it was the gazillions of tiny babies.
So check whenever you give them a cuddle, while they are watching tv, when you are waiting somewhere with nothing to do. It just becomes an automatic instinct.