Graphql : Get parent's parent source - getSource() in graphql java

Question

Let say I have following schema

type Org {
   vp: Person!
   employees: [Person!]!
}

type Person {
   id: ID!
   name: String!
   grade: String! @auth
}

I have auth directive implemented in DGS as below

@DgsDirective(name = "auth")
public class PrincipleAuthorizationDirective implements SchemaDirectiveWiring {

@Override
    public GraphQLFieldDefinition onField(SchemaDirectiveWiringEnvironment<GraphQLFieldDefinition> environment) {


        GraphQLFieldDefinition field = environment.getElement();
        GraphQLFieldsContainer parentType = environment.getFieldsContainer();
        DataFetcher originalDataFetcher = environment.getCodeRegistry().getDataFetcher(parentType, field);
        DataFetcher authDataFetcher = new DataFetcher() {
            @Override
            public Object get(DataFetchingEnvironment dataFetchingEnvironment) throws Exception {
                CustomContext context = DgsContext.getCustomContext(dataFetchingEnvironment);
                String requesterId = context.getPrincipleId();
                // Get VP of this org. Which is like dataFetchingEnvironment.getSource().getSource().getSource()
                String VP_ID;
                if(!requesterId.equals(VP_ID)){
                    throw new ForbiddenException(field.getName());
                }
                Object o = originalDataFetcher.get(dataFetchingEnvironment);
                return o;
            }
        };
        // now change the field definition to have the new authorising data fetcher
        environment.getCodeRegistry().dataFetcher(parentType, field, authDataFetcher);
        return field;
    }
}

Question 1:

As you can see, I want to get hold of Org->Vp->Person->id and match it with requesterId from security context. How do I get VP? I know that object hierarchy has Org` always. I.e query is always through Org. Just don't know how to get access to it from above directive.

Question 2:

How can I get full hierarchy of this field? Something like org { employees { grade } }

Note: I am using data loader.