All depends what game it is, how it is 'sharing' the experiance and how your 'connecting' to each other and the game. For example: BattleField, it is hosted NOT on your computer so your computer has to connect to the BF servers, then you need to 'friend' your SON and hope to get him in the same team as yours to both play together.
So telling us ALOT of detail on what game(s) your trying to play with your son, are they 'network' games (just because it says TWO player it doesn't mean TWO computers), do you have enough LEGAL copies of the game(s) (you need to buy TWO of every game), what are the specs of each computer, can the computers 'share' files to each other (you see JRPC\C Drive and he sees DADPC\C DRIVE when looking at File Explorer, then under Network for example), and so on.. There is a myriad of pieces to the puzzle here