What to recommend against dandruff? (except anti-dandruff shampoo because none of that stuff actually works)

Maybe not dandruff: Dandruff shampoos actually work quite well if picking the right one and that the problem is truly dandruff-- excessive shedding of dead skin cells on scalp caused by a scalp-specific fungus, malassezia globosa. If otc trials of several shampoos w/o success, consult doc for eval--possible causes such as psoriasis, seborrheic dermatitis/eczema etc... Good luck to you.