You cant just describe a symptom and get a remedy.

The body works by having its own personal internal doctor kicked into action.

This can only be done by looking at each individual and working out which remedy is the closest match to the character of the person.

For instance the Sulfur person is hot and untidy.--- the Ars alb person is very, very tidy -- etc etc.

From the details you give I imagine that the 11 yr old is hyperope plus one,
[ far sighted] and the other with a minus prescription is myopic
[short sighted]. Straight away the signs point in differing directions.