Actually he's been fine with onions he likes it in his gyudon.
https://www.youtube.com/watch?v=IVM5UZli5v8he also likes broccoli and asparagus despite it being a green vegetable which used to be a big NO for him, still hates avocado and even said it in english
https://www.youtube.com/watch?v=8IgDcvDrXsQ