I'm in a similar situation.. I havent had WLS... but I was morbidly obese and my parents and younger brother still are. They all suffer from high bp, my mom is diabetic... etc. They have had a lot of problems with circulation, swelling, kidney stones... the list goes on
I have offered to cook healthy food for my younger brother who I live with... since he eats fast food daily and complains about his finances. I look at him and my parents.. and it makes me really sad because I love them all... but they're choosing a bad path for their health. They see that I still eat (I just regularly make healthier choices and religiously plan meals/snacks) but they choose not to make their own changes.
I completly agree with whitelion... family/loved ones have to come to the decision themselves. Nothing I can say now will get them to that place. All I can do is lead by example... much like you have!