Are you sending him off to a pro, or are you going to do the actual handling? If it's you, then you'll be able to see how much he can handle and put him up when he's tired. August can be hot and humid over there, and I know from experience, not all the west side dogs can handle the heat well. I guess that's one positive thing about the god-awful 100F++ heat we've had over here the past 10 days or so.
I think most importantly is to check his weight/body fat level and make adjustments to his diet if needed. If you can start running him in open fields or on off lead walks in advance, that's a good start. Swimming of course as well. Anne