Once they're off the tree, ripen at room temperature for about a week. Then transfer into the fridge in an airtight container, they usually last in the fridge for another 2 weeks.
Doing fridge first means they never ripen and just dry out before softening.
When I visited my aunt she gave us several avocados, and I thought, "we're never going to be able to eat these before they go bad". I was so wrong — they stayed perfect for well over a week.
... and since they are treated with all kinds of chemicals who mess with the ripening.
Or are they used for other purposes but affect ripening?
apart from herbicides, fungicide and pesticides, there are chemicals to block the ripening while the fruit is still on the tree, because you want to harvest all fruits at once. And then you do various things for packaging.
And there were likely other purposes as well, I have forgotten now. All in all, lots of them were used, way more than I expected. So much, that I prefer organic.
It still only flowers once a year in spring like a normal tree, but by that following winter (regular harvest time), only the clusters with few siblings would have grown large enough for harvest. Then it flowers again, and then bigger family clusters reach maturity in the summer/fall.
My avocado tree when I lived in a much hotter climate would drop all the fruit as soon as it started getting hot (they would dry out and wither on the tree).
Sadly we're not in the child trade for tree game :-(
What about grandparents? Are you all set on grandparents? In-laws?
The mangoes trade pretty damn well. (Not our mango tree - but same age and same rough geographic location: https://www.youtube.com/watch?v=IgBgQQXoUw8 )
My father planted the tree (he was born in 1935) and does most of the bulk cooking | prep here still; he's a great grand parent, I'm a grand parent ... we're doing pretty good on extended family, thank you for the implied offer of surplus humans but they tend to be for life and not just for christmas.