Should my sister-in-law be concerned if others are suggesting that her son should be checked for autism or adhd? She feels that her child is normal but her mom, my mother-in-law seems to be certain that there is a problem with the child. He's 3yo, a suuper active one, knows the alphabet and numbers bec. he constantly watches using ipad, he cannot be reprimanded to do this and that etc.., he's somewhat "immune" to pain, he doesn't communicate or answers questions asked to him but commonly recites lines from videos he watched. I don't know how to advice my sister-in-law without hurting her feelings.

I would say, yes. It wouldn't hurt if you have the child checked. I have a workmate who has shared the similar situation about her daughter. Everything seemed so normal to her, but when they visited her daughter's new pedia, she was advised to have her daughter checked of ADHD. True enough, her daughter has ADHD. She was told that some parents might not notice it as they see the child almost everyday so they would think everything is normal. It doesn't matter how smart or active the child is. In fact, there are a lot of kids with ADHD who excel in academics.

My 5-year-old nephew is just like the little kid. I didn't have the guts to ask my cousin if his kid has a mental disorder. However, I just kept on asking the kid's milestones and behavior. Eventually, he opened up about his suspicion that his kid has ADHD. I guess you can try doing it too.