Politics encompasses everything in life. It is easier to break it down into bite size pieces and remember that Left or Right will have crossover ideas, although they hate to admit it.
So rather than discussing 'politics' , you can have a viewpoint on a specific subject, based on your own experience or that of your wider family or community, the demographic you most align with for purposes of that specific subject, and some people who are true believers will naturally pick a side because that is what they are told to do by whatever 'party'. I think the latter very much depends on whether the issue is local or national from experience.
That is what I tell my children, politics effects everything, you can make changes but you need to muster people power to do so. If you aren't happy with something, let those who rely on election for their wages ( local and national ) know that you aren't happy and get as many likeminded people to do the same. You might not change the Government but you could make a change that makes your life better in some way.
We are generally very passive in this country when it comes to politics and yet we could all wield a lot more power if we put our minds to it.
I would get him to start off by finding out who his local councillor is and what their responsibilities are, who is his MP and how to contact them. If he isn't happy about a local or national policy, politely let them know.
At his age, I couldn't have told you which papers were Right and Left leaning 