How do I provide unsolicited dog care suggestion without offending the owner?

Short version - from time to time I do dog walking for a client and the dog is basically an "outdoor" dog. The owner put in a small kennel for the dog. This kennel is missing a proper roof and in turn, the dog suffers from the heat on very hot days (over 100 F). There is only a tiny area of shade for the dog which may block direct sun but does nothing to stop radiant heat and general air that could be cooler if full shade was provided.

I have no idea how to tell the owner in a manner that would be effective. I worry about the dog and certainly know it suffers from the heat on certain days. Any help from Rover would be truly appreciated or if Rover could provide the info to owners.