Hi..thanks for the detailed history
Since his psychologist and paediatrician have already ruled out autism by screening him.
As you have rightly noted it is because of the absence of company of peers which has made him hyperactive.
I would like to suggest you to follow a few steps,but it requires a lot of patience and work from parents and he will surely improve.
first we do some behavioural therapy and wait for a considerable time,before starting medications.
1. spending even 20 minutes outside everyday ,even ur own terrace is enough, this will help him vent out .
2. A rewards chart at home, can help motivate him .Reinforce him to look into ur eyes and speak every time he distracts and reward him every time he follows with a star.
3.Give a balanced diet containing all vegetables , fruits and good quality protein.Allow self feeding and monitor him.
4.Try to spend more time with him,if you notice him talking to himself go to him immediately and initiate a conversation.
5.Teach him simple house chores and make him to do it along with you.
6.Find out what he likes -eg: colouring or football and encourage him to do it everyday.
7.Restrict screen time
Next Steps
Pls consult if u require more details.