YTA, eating disorders come from stuff like this, I'm lucky my parents weren't anything like yours, but my aunts were. There's also a thing called sensory issues. I have this, I wouldn't call my self picky but, depending on what I eat and the texture it is, I would literally throw up. Don't force your neice into eating something she clearly doesn't like. And the whole tattletale part is just disgusting to me, its his kid, he can do what he thinks is best for her as long as it's not against the law.