Cetaphil cleansing lotion is the most mild face wash She can use that

Greetings. You can use any gentle cleanser like cetaphil or episoft or moiz - which are soap free cleansers for sensitive skin. They are good but may not eliminate oiliness of the skin in case your child has oily skin. Any how - children rarely secrete too much oil from the skin before their teens, so the above cleansing lotion / face wash should suffice. Hope this helps

Yes because kids have softer skin so avoid harsh face washes. Continue using a mild soap like dove or pears for the whole body (including the face). And keep washing of the face to a minimum (my recommendation is 2 times). The more one washes face the more it can loose its natural moisturizing factor.