dandruff advice, please <...dull and unsexy warning>

[vivariumvivariumsvivaria]

13 year old boy - has always had a bit of a flaky scalp, but, the last year has been grim. He's dark haired and you can see flakes from a distance, school mates are commenting.

We've tried T-gel, head and shoulders, neutrogena and coconut oil soaking in overnight. He washes his hair twice or three times a week. He's starting to get a few spots and a bit of greasy hair, but, it's not too bad. Has shaved once, so, puberty is going on, but, I've never heard of dandruff as a puberty effect.

Any advice? Poor kid's getting self conscious - not really ideal when your body's doing weird shit all over the place, really.

TIA

This is just brilliant, thanks folks.

He's all smiling now we have a list of options to try. We've agreed we'll give it a month and if no change - GP.

I do still think "GP, for...dandruff?" but, it may be something dermatological and seeing as how I'm heartened to see some of you have done that. Don't want to be wasting anyone's time!

Thanks for the advice.