There's no reason not to listen to the advice of older siblings. After all, they're spending time in the home and they could be blessed with some rare insight. (Insight is always ok to "hear.") Not long ago, one of our college kids was home for awhile. This kid is incredible with his brother. Takes him to town with him, plays games with him and sometimes rewards him with computer time on his own laptop. Big brother & sisters are all grown & generally away from home but having some time here allowed our oldest son to see the day-to-day behavior and sometimes CHAOS that can be our routine. He had a couple thoughts that we heard him out on, implementing some strategies immediately. Nothing wrong with hearing others' thoughts. Especially when it's someone who really knows & loves the family. (I'll take my own kids' suggestions over some people's....just because my kids truly understand all angles.)
I do try to be gracious to anyone offering their home-grown wisdom. I don't argue or put down suggestions. (The truth is, they don't live with us so they'll never know if we implement any of their ideas!) Parenting a high needs ADHD child is tough. It is my belief that this job can not be done without continual research and improvement as a parent.
Bobby's worth everything we're putting into parenting. We want him ready to be successful outside our home in a few more years!