patrice1

You can't. He is not ready. As painful as it may be for you to watch, you can't make him change. You can't preach him into change. He is an adult and he is simply not ready.
That said, you know that he is noticing what you are doing and how you are doing it. His passive aggressive comments and actions show you that. His weight and choices are on his mind as you can tell but he is not ready. Think back to your obese days. None of us made the decision to get healthy until we were ready. Some of us thought about it for a long time and the decision came slowly, some got ready via medical issues and scares but we became ready when we became ready and not before.
Your brother knows what he is eating and what his physical shape is. He knows what WLS is. I'm sure he already feels bad about himself, what obese person doesn't. When people remind us of it even in the context of being concerned, it can send him into an unhealthy binge. We have all been there.
Just be there for him and love him. Be a good example and only relate your experiences as they relate to you. Otherwise you will come across as judgmental and a reformed zealot. No one likes those. Think reformed smoker who preaches to everyone on the dangers of it. Really? Smoking is bad for you? I did NOT know that!…..said no smoker ever! You get my point….