Pretty old apple tree in the garden which produces hundreds of not-great-tasting apples every year looks like it’s in a bit of a state. I had to cut back a weird branch that had been cut before, presumably because it shot out horizontally, and there’s a ton of rot.
It’s not in danger of hitting any buildings if it ever does fall, although could maybe take out a distracted child or two if I’m lucky.
Is there anything I can do to save it?
You could try pollarding or coppicing it in the late winter.
During the winter all the sap drops to the roots for storage. If you cut it all off a few inches from the ground you’ll get rid of the rotten bits and in the spring the tree will just start over, but with a bunch of root.
There’s some resources you can google if you use coppicing as a keyword.
This is a layperson’s advice, so grain of salt and all that. An arborist would probably know better.
If the little bit of greenery at the bottom is saved, it'll probably stand a better chance in the spring, but it'll be tough to cut out all the rot and leave just that.