Just because he's so stinky right now I'd take him to the groomers and see how it goes, having a professional do it who is used to that sort of behaviour and is better equipped to handle it should get the job done
Then a few days after I'd work hard on desensitizing him. Have him in the general area and pool and work slowly and very positively on having everything from the hose to the shampoo be a positive thing. Something as simple as touching the hose while not having it move can be a victory, the more you show him it's not something to be scared of the easier it will go.
Right now the pup doesn't trust or know you very well, you need to build that bond and associate yourself with peace and safety. The more he gets to know you the better he will trust you
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 6 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010