Oooor... it could just be a case of sibling rivalry gone a little overboard. There’s not nearly enough information here to make a snap judgment like that.

If the girl's father is participating in the SIBLING rivalry, there's more issues at hand than harmful overeating and sympathy vomiting. Even if it is just "sibling rivalry"- a concept which is bullshit by the way- overeating to the point of vomiting isn't something that develops overnight, which means that chances are extremely high that OP has known that the men in the family have been eating the daughter's dessert and done nothing about it, which is just as bad. There isn't a way to spin this that takes the blame off OP and the husband for being shit parents.

You’re assuming this is a regular thing, which I highly doubt given that OP only just learned about the sympathy vomiting. For all you know, this was a one-time joke/taunt that got out of hand (“we’re all gonna eat your dessert if you don’t finish dinner, ha ha”) - unfortunate and unpleasant, but not necessarily indicative of shitty parenting.

You said it best. OP, stop force-feeding your kid. She'll get fat. Portion out the desserts before hand so that it's assured she'll get her share when she's ready to eat it. And control the boys of your family. If they're teasing her, it's your job to put a stop to it.

DraconicFeline- the FATHER and brothers used her not finishing her dinner as a threat, meaning that she tried to eat EVERYTHING ALREADY ON HER PLATE. If the amount of food on her plate was enough to trigger vomiting, it was too much food to be on her plate in the first plate. The fact that she ALSO fully believed that her father and brothers would eat her dessert and that her mother WOULD NOT stop them from doing so indicates that it has happened before. This was just the first time that the daughter has vomited- at least, in sight of the rest of the family.

Try to shake off a few assumptions and reread this FML with an open mind! All we know concretely is that she didn't want them to have her dessert and that she threw up because she overate. Couldn't this mean that they were just in line for her leftovers (no "threats") and that she loves sweets so much that she wanted to finish it all herself? It doesn't mean they forced her to overeat! The size of her portions might not be bad - maybe she ate a lot at school, had a big afternoon snack with a friend, or had an upset stomach already! I had an insane sweet tooth as a kid and probably went almost as far once or twice. My family wasn't abusive at all and I definitely didn't have food anxiety. I just loved eating!

It IS a regular thing to do things like what they're saying, though. My mom has talked about a family member not letting her leave the table unless she ate the FAT from the meal(she never did her parents came home and weren't having it) perhaps they're a bit aggressive but..its common to do shit like this to kids and it did sound like the daughter was given reason to worry. It's also not uncommon for people to eat other's food. I've had people-including a stepfather- take food that's supposed to be mine. So let's put it this way. If this was due to the daughters own panic with no given worry- try to reassure her it won't get eaten/she doesn't have to eat so much. If she was given reason- totally with Ghost here. Even if she wasn't given reason here- try to see why she thinks her brothers and father will steal things that are hers. Is it a normal occurrence elsewhere?

Wait—how did you come to that conclusion?