Dad is a self made millionaire (I only mention this as any suggestions are achievable). He worked so hard his entire life but after he had his knee replaced, he developed severe fluid retention in his legs. I have researched this to the max but dad won't do the exercises, I never thought that would be a problem for a man like him. He stopped working at sundown and went and had the op the next day. Therefore, there was no semi-retired it was just bang he could not work with his much-loved cattle. He has never watched TV except the news then he went to bed. He hates all movies, all TV shows, I have found a few old comedies on YouTube for him. He does love rugby league football ( I am Australian and so is dad, our family has been here since our ancestors came here as prisoners ). I live with dad now on our home ranch. I was taking him to cattle auctions but he stopped wanting to do that plus Covid certainly does not help. My brothers and I bought him a buggy, not sure what USA calls them, so he could drive around his land and tell us all what we were doing wrong. ( We thought he would like to feel as though he was still the boss so to speak ). He has no interest in groups or clubs. Absolutely any suggestions would be welcomed.
Maybe as he adjusts he will find new interests or a new viewpoint but it sounds like you are very much there for him which will help.
Maybe make him an outdoor sitting room so he can lounge in the middle of the outdoors. But I would think the most important thing is trying to make his life as close to like it was as it was before.
I lived in Australia for a couple of years in my youthful youth. Happiest time of my life, I felt very much at home there. :)
Perhaps he could develop an interest in finding a new star, or seeing the different planets. Something new and different to learn about, and knowledge that he could share with his family.
Was he on antibiotics after surgery, like Clindamycin? My mom (90) took this for a dental issue and it caused her legs to swell with water. We weren't aware that it is not recommended for seniors due to this problem.
Also, are you aware that anesthesia can sometimes create a lasting cognitive problem in seniors? He had a major surgery and I'm assuming he had anesthesia for it.
"Postoperative cognitive dysfunction (POCD) – This is a more serious condition that can lead to long-term memory loss and make it difficult to learn, concentrate, and think. Because some of these problems are already common in elderly people, the only way to determine if a patient actually has POCD is to conduct a mental test before surgery. Certain conditions, including heart disease (especially congestive heart failure), lung disease, Alzheimer’s disease, Parkinson’s disease, and having had a stroke in the past, increase your risk for POCD. "
source:
https://www.asahq.org/madeforthismoment/preparing-for-surgery/risks/age
If you didn't live with your father before his surgery you may not have been aware that he had some cognitive decline already because casual contact with him may not make it obvious. POCD may explain his rather "sudden" change after surgery. He also may be suffering from depression, and should be discussed with his physician. I hope your efforts result in some improvement for him but I would have some very tempered expectations. May you have peace in your heart as you go on this journey together.
There are some flourishing outback social media groups. You might like to look for them. Dad might enjoy discussing business on line. Advice might even be a new business!