Yeah you can do this easily, just detect the order of the autocast ability then move or create the new dummy unit/hero with increased range while hiding the original then same thing back and fourth.
You need dummy units because they're better to use then 4000 upgrades.
I'll even give you the method to detect this since the guy above me doesn't know as well.
[trigger=]
Events
Unit - A unit Is issued an order with no target
Conditions
(Issued order) Equal to (Order(healon))
Actions
Game - Display to (All players) the text: test success
[/trigger]
To detect when it is turned off you would do healoff. Same goes for every other autocast spell, you don't detect them by spell events however you can use order events.