How to help parents?

My Father is a businessman, he worked hard throughout his life & luckily all of us (siblings) did good in their life. Everyone is on their own now.. Sisters are married & well I am outside trying to be something.. and my parents are at Home..

My Father is still doing his business but it's not running too well. I try to explain them that there's nothing to get stressed.. you know, just earn enough, have fun, travel, maybe go to temples, take it slowly. Luckily we have enough funds to survive & even live a good life. But somehow he's in pressure always. He hates the idea of being retired (which is pretty much understandable) He's like - why I need to retire.. this is not my age to retire. He's 58.

And I'm fine. I have nothing against him & his work. Do it. That's fine. But don't take stress. That's not good for his health. I'm actually scared about this.

Also both of them are alone at home. And I'm usually tense about them. How they must be feeling. The loneliness. Boredom. What if they get sick. What if something happens. Etc etc. I don't feel good, when I see how they worked hard all their life & now when it's the time.. no one is nearby..

I can definitely ask my parents to shift with myself, but my own life is pretty much volatile rn. I wanna stable in a year or two.. then maybe we can.. but for now I'm not sure.

So I'm asking here, What can I suggest my parents to do? What businesses they can try? How can I keep their life fun, exciting, engaging? How can I comfort them to not take stress about work.. and take a bit rest in their life?

Any help is appreciated. Thanks.