Rub-downs with water are more likely to dry out his skin further...I wouldn't recommend it. I would ask your vet about a fatty acid/omega 3 supplement. It works from the inside out and can be a big help for dandruffy skin. You can usually pick these up from any pharmacy/health store, but I'd ask for a proper dose.
Solomon - black DSH - king of kitchen raids (11)
Gracie - Mutterooski X - scary smart (9)
Jaida - GSD - tripod trainwreck and gentle soul (4)
Heidi - mugsly Boston Terrier X - she is in BIG trouble!!! (3)
Audrey - torbie - sweet as pie (11 months)
Patrick - blue - a little turd (but we like him anyways) (6 months)
Boo, our Matriarch (August 1 1992 - March 29 2011)