Your 10 year old may use the following: (in this order and 2 x p.d.)
Cleanser, soapfree and wash and only one to rinse off.
Beta Hydroxy Gel, as toner and ex-foliater. Apply a few drops on face and leave on.
Safari SPF40 Sunscreen, which acts as sunscreen as well as a safe moisturiser that does not block pores.