The general sentiment behind all of this is doing everything that you can to help him and his business and to respect his time.

The public sentiment has shifted drastically, as people realized that now, the paper dollar is not backed by anything, which lead to massive capital flight to assets and everyday purchases, fueling inflation to unseen levels of 15% in the end of 70s/early 80s.

To echo some of the sentiments above, they should ask WHY they want to break the lease first, for context.

I agree with your sentiments on fees but I explained my rationale for paying some of them, in line with Steve K's thoughts.

There would also be a part of me that would like the sentimental value of owning my father's house. 

I guess I could understand if it were 1 or 2 if those properties had some sort of sentimental value to someone who has that kind of money, but it's happening far too often to be isolated events.

I mentioned in the housing market report for March of 2022 that there were emerging data points indicating some shifting in market sentiment.

The sentiment of your original post suggests you value but don't need the rental income, you're unsure about being a landlord again (refers back to #2), you have a business venture you could use capital for but you're concerned there's future appreciation you'd miss out on.  

Make sure you know the ordinances where you property is located but also make sure you understand the sentiment with respect to STRs as this can dictate future ordinances.  

I share your sentiment exactly about the cyclical highs as I was caught "holding the bag" from a purchase I made in 2004.