I'm thinking of a character that fits the "Mrs. Brown" description from Turkey City lexicon.

Spoilers about short story that raises this question below. You can stop reading here if you just want to answer this first question.

I'm at a cross roads right now in my short story "it should be easy" one road lets the MC save the Mrs Brown from harmimg himself the other has Mrs. Brown harmself while the MC tries to put him back together again.

Are both okay? Is one more of a "conciet" than another?

I'm really torn. I've already eliminated one conceit but now I find myself facing another.

What I mean is, I felt that if I wrote a specific scene a specific way I was doing it simply because it made the story more easier to write, ie a short cut(this is a short story after all). Yet I sort of felt that it was "cheating" to drop such a scene because I wasn't sure if I had communicated/foreshadowed the predicating events.

In the end I didn't cheat. I've actually chosen for now to keep the character from take the action that I felt was "too easy"

 

That's how Michael O'Donnegue ended his article on writing in the National Lampoon.

On the other hand, I just finished book 7 of Anna Karenina, and so I know that a character can be both sympathetic and self distructive. And you seem to understand that you must show this character has self destructive tendencies long before the big bang. (Maybe his friends try to talk him out of going off his meds cold turkey.)
 

If not, maybe it just doesn't belong in a short story at all? But if it does, well then, even if it's not what the readers expected or will make them sad because they've grown to like the Mrs. Brown character/come to relate to her (and by damaging that character, you're now putting the reader's faith in the goodness of humanity at risk) - well...we all have to cope with disappointment from time to time. It's not your job as a writer to shield us from that. This, truthfully, has been one of the harder writing lessons for me to learn. I apparently feel compelled to write happy, sunny fluffy stuff where no one ever faces conflict or sadness and everything always ends well. Bah! No one will read that crap! I'm teaching myself to write the grit, the guts, the real stuff, but some days it's a struggle as I seem to gravitate toward trying to end each scene happily. What I think works better, particularly in short fiction, is to raise the stakes over and over, put the reader on edge again and again. Only near the end can i let them off the hook.

I hope this is helpful!

 

As far as your choices (prevent or cure Mrs Brown's problem), I'd guess either could work just fine. I would pick whichever causes your MC the most conflict and struggle. In other words, which option shows us more about what the main character is really made of.
 

The most important thing to remember is that whatever choice you make as a writer must make sense for the character. Just make sure you lay whatever groundwork you need to justify what's coming; as long as the behavior doesn't come out of nowhere, write what works for your story.