I could be wrong... But I don't think a person can really enable symptoms. The same way they can't fix symptoms. And aren't responsible for symptoms. They can enable bad behavior, but bad behavior isn't a symptom.
To use your example:
If (he's canceling because) he's too stressed to go? That's symptomatic.
If he's being a dick about it? That's bad behavior.
To use one of my fav examples, ever: (illustrating what happens when people try treating symptoms like bad behavior, and why that doesn't work).
http://i.huffpost.com/gen/2271298/thumbs/o-ROBOT-HUGS-570.jpg?6
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Another way to think on it?
6 diabetics are sitting at your dining room table. You serve each of them a piece of cake.
Does Not Eat Cake
1. Oh! Sorry, I can't eat this, but thank you! :D
2. You f*cking bitch! How dare you serve me cake! Use your brain! :mad:
Eats Cake
3. Thanks! ... And having planned in advance for cake has modded their diet, and brought along extra insulin, suffers few/no ill effects whatsoever.
4. Thanks! ... And not having planned on it, still goes about things as responsibly as possible.
5. Thanks! ...And ends up in the hospital. Again.
Is Convinced/Forced To Eat Cake
6. Only after you have teased, begged, guilt tripped, manipulated, and otherwise pressured them... OR... After you have held a gun to their head, after you hid the pulverized cake in their bitter veggies whilst lying to them about what's in the dish, etc.
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Okay! So which is your fault? Only #6, right? That's the only one you're responsible for. All the rest? Is ENTIRELY ABOUT THEM & THEIR CHOICES. Their behavior. Their choices.
Okay... Now which of the 6 do you have any control over their pancreas? None, right? And neither do they. They each choose to deal with the effects of pancreas in their own way, and some are going to be better at it than others, but neither you, nor they, can have a stern talk (nor reward, nor punish, nor in any other way manipulate) their pancreas into producing the right amount of insulin to be able to eat cake without any ill effects. In NONE of these examples does your enabling cake, or withholding cake, in any way affect their diabetes.
So when you're asking about "enabling", like the cartoon linked above, (or my piece of cake example) one has to be pretty clear about what's behavior & what's illness. You can enable behavior, but not illnesses/injuries/symptoms. And, at the end of the day, their behavior? Is still their own darn responsibility.