7 years child continous stay

[Bigyou]

Good day all,

Please i would like to enquire about the 7 year child route. I have a son who has lived legally in the UK for 8 years and 10 months. He has been dependant on me all the while but would like to see if He is eligible to take the route of child that has lived for 7 years.

What does continous stay in the UK mean?
Does it mean if he has travelled for holidays outside the UK then he is not eligible?

What forms can be used to make the application?

Is there a guidiance document for this route?

Please advise.

Thanks