My brother has had bladder issues for years. It involved having to "go" very frequently. Most troublesome at night. He's had his prostate and kidneys checked out and he doesn't have any rollings. He also developed a white patch on his tongue about ten years ago that hasgotten progressively worse. He's lost most of the taste buds. He was diagnosed with hashimotos about four years ago. I've been after him to go gluten free for the last two. He finally did about nine months ago. His bladder issues are a thing of the past and only flares up when he Has gluten. His tongue is slowly improving.
I second the suggestion to have your client try a trial of gluten free.