Conversation during patio visits/ in-room visits?

Yes, pictures, and funny animal or people videos on YouTube to make them laugh. You can read them News of the Weird stories, bring them "odd" or unusual foods to sample and discuss (like star fruit, Impossible burger, smell exotic spices and talk about where in the world they eat those things and how they're cooked); for vets you can look up videos on the latest and greatest war weapon demos (my BIL works at Raytheon and every once in a while he shows us some astonishing stuff!), play the Guessing Game (if your LO has good feeling in their fingers) put an item with interesting texture in a paper bag and pass it around have people try to guess what it is; same with smells (guess what spice), etc. I have unearthed old letters and cards written to my LO from her sons/grandsons and I give them to her to reread.

Even though my MIL has had short-term memory loss since 2015, it is almost impossible for me to avoid saying "do you remember" in a discussion with her, so you're not alone!

For me, your story is deja vu all over again. Your age, your vacations, your marriage (my wife and I were married for 52 yrs also.), you having to place your wife in MC all seem like I could have written your story. It sounds like you had a wonderful marriage. Savor those days.

What do you talk about? It depends on where your wife is on the dementia spectrum. If she's in earlier stages and is still conversant, you can talk about most anything, family, weather, current events, etc. When conversation and understanding gets more difficult, forget the current events and weather, do more reminiscing (you can always do that regardless of her stage). Your wife may not remember any recent events but she'll remember her teen years, your dating years, and her long ago life. An old photo album is excellent. Regardless how advanced she may get, always talk to her. It may become more of a monologue on your part but she hears you. And if she can, give her time to respond, her processing information has greatly been affected. In my wife's final days besides reminiscing, I resorted back to telling her what the family was doing, where should we go on vacation, what we'll order for supper and anything else that came to mind. The words don't matter, only the sound of your voice.

When talking wears out, play some music of your and her generation. Did you have a favorite song? Did she like music of the 50s, 60s, 70s? Find a music app on your phone and play those oldies when you visit. Pandora and Stingray are 2 good apps. They have many genres.

And good for you in deciding to attend a support group.

When I visit with my dad I find that it really isn't a "conversation". It's more like I am writing a oral letter with me talking about things that are happening in my life and with my childrens' lives. He'll ask a few questions or confirm his understanding of what he remembers ("They live in XXX, don't they?" "I was there when I was in the Navy." ) Sometimes he's right, sometimes he's wrong. Asking him questions is pointless and frustrating. If I say "Did you go down to breakfast?" he'll say "I don't remember." I find that to be sad for both of us so I rarely ask a question unless I already know the answer and I preface with something like "Charlie is learning to ski. Didn't you ski when you were young?" I try to give him a verbal prompt to the answer. Over time we just have the same conversation over and over and over. It's best if you take over most of the talking and don't ask too many questions. I have about six "canned" conversations that we rotate through. Old pictures are always good for conversation prompts. I find that the really old pictures I have of his time in the Navy and when he was young are the ones he really enjoys.