If I was Bob I'd move the boat upwind of the fish but it might scare the fish so I think the answer you are looking for is he should use a backhand cast or a roll cast.

I'm gonna take a wild guess and say Rusty gave Bill a strike-indicator. Either that or he has Bill wiggle his rod tip at the end of his cast to create slack.

1) either cast across his body or (looks stupid but I've seen it done) cast backwards: cast regularly but away from the target, laying down your final "backcast". don't think a roll cast will work; if a 20mph wind is blowing in his right ear, how does he keep a big enough belly far enough off to the side to make the cast? he'll end up rolling it right up his back and into his hat.

2) if the shaking is causing refusals it has to be a dead-drift issue. salmon in alaska don't feed on the surface, so you must have put on an indicator to act as a damper. either that or you switched to a streamer pattern like an egg succking leach so that the shaking works for you, rather than against.

1. Have Bob stop his backcast earlier to get his line higher in the air before casting it forward. If the wind was too strong, I'd cast over my left shoulder with my right hand.

2. Give the line some slack to absorb the shakes from his regular return customer.

might I suggest the Dutch Rudder

1) Change the angle of the rod, casting overhead but with the line off the left shoulder.

2) Switch from a fly rod to a spinning rod and bubble. Or set the drag to nothing and allow the line to slide out the guides as he moves.

I like his go to it ness. it sound like he never gives up on something he loves. I would duck my head when i cast so it dosent hit him.

For the first situation, all Bob has to do is turn around with his back to the fish and cast normally as if you were facing the fish, just shoot your line on the back-cast and drop the fly into the reds. FISH ON!!
The second situation, I would switch Bill to a bunny leach, the twitching gives it some real action. He could also tie on a popper or mouse pattern, I have taken several salmon on dries. Especially Coho's, Pinks,Chums, and the occasional King.

I would say son of a ***** and keep trying. Then when I got home I would try that cast over and over until I don't hit myself in the head.