What Is The Solution To Manage An Inobedient Restless Toddler With Sleeplessness?

Concerned for my nephew 2.3 yrs age. I have noticed that he is not listening to directions simple come inside can you put on your hat etc... also he moves round the room opening cupboards moving through hall looking in draws etc when ask to come here he continues not listening. I have checked out his listening skills as it is like he Is focused on exploring and blocks out everything else he talks to himself which I cant understand the only things he says is simple names for members in his family repeating the name if it is mentioned to him like mum he says mum in car, dad in car mum car dad car. so he is aware when his parents are not at my home. he has squint in one eye but not bad and plays purposefully at different areas on his own. he dosnt acknowledge his baby brother or other children if they are playing alongside him. we recently visited a train park where I was taking other children 21 months 4 year old and his 7 month old brother when waiting in line he couldn't control himself he pulled away from my hand land ran around to the front of the line crawling through someones legs at one stage over a period of a 2 hour period between walking around in a group and me holding his hand I had to carry him most of the time he ran away 14 times to the outer areas of the place and 8 times straight towards the train as he couldn't wait. also on eating lunch he sits up at the table opens up an item puts it to his mouth and then moves onto a sandwich takes one bite then gets down from the table and this goes on after just about every 3rd bite. he also still has a bottle of milk in the middle of the day then followed by a sleep with his special giraffe toy which he sleeps for up to 2 hours when he is up again he is off exploring again. should I express my concerns I have tried to dance and sing action songs with I have the other children over too to see if he will join in and he smiles jumps round enjoying the music and then moves on. concerned weather or not I should say something or should I wait and observe I have had 15 years caring for children from birth to 6 years and feel like a little professional advise before taking the next step