Maybe your 'rents are conscious that the brother was most unlikely to achieve that goal?

Don’t count on others to be your cheerleaders. Learn to feel good about your own successes. It’s something I learned a long time ago from my grandfather. When you do a good job or achieve an important goal take a moment to savor it. Don’t gloat or brag, just acknowledge your successes to yourself… OP it’s unfortunate that your parents didn’t notice you had reached your goals. But be aware that weight and fitness goals are achieved gradually and the people who see you daily may be the last to notice the improvement.