NATIVE ENGLISH (USA) TO PICK UP KID AT SCHOOL

I am looking for a native English speaker from USA to help my child to maintain his English. He is 11 years old and he already speaks English, as we have been living in USA for 3 years. The idea is to pick him up at school two days a week (Monday and Wednesday) at 6:00PM, come home and stay until 7:00PM talking, playing and having fun with him in English.
Area: Metro Sainz de Baranda –line 9- and the school is 3 metro stops away in the surroundings.

Starting now till end of May 2018. Minimum 3 months.
Price: As this is not a formal class I am offering 10€/hour