husband told them he wasn't sure that he should have brought her there because he wasn't sure that she was serious about killing herself and when questioned difficult child's response was "O yeah? I will, too!!!"
That's the response of a brat who has absolutely no intention of committing suicide.
However, such a brat is quite capable of doing serious self-harm in an attempt to be taken seriously (out of desperation to deflect and distract from the crux of the matter, which is her own transgressions) and that could result (accidentally) in her killing herself. It wouldn't be suicide, but could be just as fatal. However, she is more control than that, I feel.
That said - I do agree, taking her to hospital was the right call. She threatens self-harm, you take it seriously even if you're fairly certain it's a bluff designed to deflectattenion away from her. And also a way to alleviate boredom from being grounded, as well as to punish you all for catching her out.
DO NOT LET HER WIN.
No softening of the approach simply because people feel sorry for her.
Think - if she were a bloke who had killed his girlfriend because she threatened to walk out on him and he is later on remorseful and suicidal, he would be placed on suicide watch but the charges he faced would not be lessened simply because he was upset.
OK, what she did wasn't in that league, but te same principle applies. Her current "depression" was not the cause of her misbehaviour. Chances are getting caught for it, is. But as long as her misbehaviour has an independent cause, then she has t wear the consequences. The depression has to be dealt with, as part of her lerning to face consequences. When you do the wrong thing, part of the consequences should be, feeling bad about yourself. it's called "conscience". She needs to get to know her conscience and learn to use it constructively, not to fight it and try to avoid it.
Here's hoping the people at the hospital will be awake up to her.
Marg