American teacher for teenagers

I am looking for an American native  teacher for my two teenage sons of 12 and 14. They are fluent in English and the objective of the classes is to maintain their level by challenging them to think, write and speak about different topics: literature, science, nature, history, American culture/music, etc

They will be taking the Cambridge C1 test in June 2023. 

Classes in the afternoon, at around 6.00pm please. Online or in person (Madrid) once or twice a week.

I am looking for someone with experience with this age group, who is willing to help them grow and develop :-).

Thanks!