Honestly I don't have any other suggestions, sounds like you have tried everything, even stuff I wouldn't have suggested like hiding food for the very reason it failed, but hell anything is worth a try when a child isn't eating. If terminating isn't an option then all I can say is that you will just have to let it go. You really don't have too many options, either terminate because there is nothing else you can do, or carry on the way it is and try not to let it get to you.