Lots of people on here started a bit that way... the meds lull you into a false sense of security... everyone in my family moaned at me and my brother when they noticed what we were eating on low-carb... my sister especially went nuts at all the cream, butter, cheese etc that we are eating...
Now she is med-carbing - even eating mashed cauliflower instead of potato - just to lose weight and get her blood-pressure down...but it took a long time to convince her...
Keep working on your uncle - it might be better, by the sounds of things, if he doesn't go to the meeting...