Hyperactive. And advice accordingly.

Hello Sir My Grandson aged 5yrs is very naughty and mischievous boy. Never care elders. Gets angry within no time. Hits others(incl parents) , shouts loudly. Very adamant. Never responds immediately when called. Doesn't maintain eye contact. Lacks concentration. Very impulsive. Doesn't sit attentively in on-line classes(UKG). Always losts and plays in thoughts of planes, war planes, crashes, sub-marines, space travel, blasts etc. Keeps everything in mouth. The brighter side is that he is very intelligent with good grasping and memory power. Screen time also very minimum. We are allowing TV viewing weekly once only, at that time also insists on watching shows and cartoons pertaining to planes,  submarines, ships etc. His naugtyness and tantrums are becoming unbearable. He has a little sister of 8months old. Father is an IITian and works in Sr Management cadre in Public Sector Oil Co. Mother did BPharm & MBA. Pl suggest any remedy and advice accordingly. Thank you.