First of all, your grandson is experiencing impulse control difficulties and endangering himself...which may turn into harming others. He needs to develop coping strategies and understand the consequences for his misbehavior. He must be rewarded and praised when he is only behaving appropriately. His attention seeking behaviors are getting the attention that he desires. Do not place so much attention on the negative behavior. One way to assist in focusing on the positive behavior is to place him on a behavior contract. Every time that he has a great day without any episodes, he will receive a sticker of some sort that he likes. After 5 stickers, he would then receive a treat or a special outing. On days where he has episodes, he receives nothing. This may take a while but once your grandson sees the consequences of good behavior, he should improve. However, if his behavior remains completely out of control, then I would suggest a visit to the pediatrician for further evaluation.
If this has helped, please ACCEPT. Have a great day!!!!!