N.W.
Add TEA TREE OIL to his normal shampoo...and shake it up. This helps with the dandruff AND prevents lice. (lice can't stand tea tree oil).
coconut oil for his dry skin. My son has eczema, and organic coconut oil is the only thing that helped his dry skin.
If it's some kind of infection, I've heard that you can use scope on his head. That clears it up in 1-2 applications.
If it's some kind of cradle cap: olive oil to soften, then sugar or salt as a scrub,....rub it around gently for a while, rinse off the sugar, shampoo off the oil. Cradle cap will clear up after 3-4 times doing this.
I've also heard of using head and shoulders once a month on just the worst dandruff areas. just don't let it go in his eyes. give him a washcloth or towel to cover his eyes while you rinse.
good luck - let us know how it goes.