Shame on me! I forgot the most important part of what should have been included in my initial post. When we got home I left the car and turned on Waze and did a new search. Viola! Waze had sound. I don't believe it's strictly a Waze issue.
I do recall a time before Waze ever existed that I somehow turned off texts, maybe calls, and perhaps other interruptions that could distract my wife while driving. It seems to me that it's either a iPhone setting or an app. i looked at my wife's apps and I didn't see anything there that looked like the source of the problem.
Could you tell me more about Do Not Disturb While Driving (that doesn't show up under my DND tab, but that sounds like a logical place for a solution)? I just reread your previous post. Are you saying that while in the car and driving, that I should go to the Settings > "Do Not Disturb," where I'll see a link for "Do Not Disturb?" While Driving?," then tap on Activate and Set to Manually? If so, I don't have Car Play. Does that change anything?