Not to worry, the hedonic treadmill means they'll be just as happy as everyone else! (right?)

No, according to the hedonic treadmill theory, people in general have a tendency to return to their own previous happiness level. The hedonic threadmill doesn't say anyting about comparing happiness levels across individuals.

So how should we treat chronically ill people? As I have some in my circles, and would actually appreciate insight.

Exactly, so if you're well, but then you contract a chronic illness, one that leaves you in constant pain, you'll eventually "return to your own previous happiness level" right? So no big deal?

Set aside the hedonic treadmill for a minute. Let's suppose it's bullshit.

What remains in your opinion? What do you tell to a chronically ill person?