LOL, that sounds a lot like my kitchen. I eat a lot of cereal.for example my version of a kitchen is just a small refrigerator with a microwave oven on top and a toaster on top of that, i like to eat frozen dinners.
Is your place rented? Do you have a deck? You could always make him some kind of catio so he can get out for a bit of air.
@Kieka made her cats a great catio so they can get in and out of the house when they want to. Lots of pictures here.
Catio Incoming
You could make the green house coyote proof by building a catio around it, so the green house is the cat's shelter and the fence around it keeps him in and other animals out.
It would need to be a bit like a chicken coop, with wooden fencing posts and wire mesh sunk into the ground.
If you're handy and you like DIY projects it's really fun to build that kind of thing yourself.
My cat enclosure has been a work in progress for the past 4 years, I'm always modifying and adding to it.
If you check Google you'll find plenty of pictures, free plans and ideas.
catio pictures - Google Search
Otherwise would your dad agree to keeping him indoors just at night? It would make him a bit safer. One of my former feral cats lived as an outdoor tom for at least ten years. It took me about a year to convince him to stay in, but it was worth the effort because he got to live out a comfortable old age as an indoor/enclosure cat.