ok so here is the thing. Exercise does make a difference. I am not saying that it's bcz you are fat or over weight or lazy as said by your brother in law. First and first of all look at yourself without any ego and see where you need to improve and be Determined. Focus on your own self. don't bother what the world says. work hard eat good food be humble gentle but most importantly don't stop. keep moving forward. sometime it's ok to be selfish. Focus determination and patience are three big things. With every single step you make , no matter how small, remember you are moving forward. with every step you go one step closer to your goal. Don't worry.