I have no problem inventing answers for the purpose of changing the subject, but some topics lead to follow-on questions or requests that make that difficult. My wife has Alzheimer's and almost daily she asks about her parents. In fact it is usually multiple times in a day. They are of course dead and have been for years, but the news is distressing to her. But if I try any other answer, she wants to go see them.
Another example is that she frequently asks me where our dog is. We've not had one for more than a decade and I don't really want to have the added responsibilities of taking care of a dog. But I do consider whether that might be the best solution.
You don't want to be caring for a dog along with caring for your wife.
Don't get one. It won't solve any problems (unless it's a problem that you DO want a dog.) You'll just find yourself with more responsibility and your wife probably won't care or perhaps even take notice of it.
When she asks about her parents, the therapuetic fib comes into play. "Oh, hon, today's not a good day to go visit them. Let's (fill in the blank) and we'll plan to see them soon. That alone might be enough to change her questioning. Telling her everyday that they're dead may just be adding to her distress.
Remember, what you have to do is enter HER reality, and suspend use of yours.
You are attempting to give her temporary comfort and emotional support, and you are not obliged to offer her facts.
Doggy is at the groomers at the vet’s at the dog park sleeping on the porch and I don’t want to disturb him.
Doggy is at the vet getting her shots. Doggy went for a walk with neighbor. Doggy got away, someone found him, they're bringing him home after they get the burrs out of his fur. Doggy went a'courtin.
A new dog might confuse her because that's not the dog that she holds in her mind and heart. Don't get a dog! Your wife will get worse, and you don't need the hassle of walking around your neighborhood behind Doggy and picking up poop with wife at home trying to plug in electrical appliances, only she's plugging them in the old phone outlets. This happens.
You don't want to be giving worm medicine, or flea treatments, or have dog hair clogging the vacuum. Or any of the other wonderful aspects of dog ownership (?).
Good luck! You do have your hands full.