I believe that’s currently not possible and I understand that it is a huge limitation. Would you mind to open an issue in the parse-server repo? We can work on that.
You can get the full parent object using a GraphQL Js schema merged with the auto generated schema. Currently parse resolve directive seems to do not support parent object.
If you want to customize the api, I suggest you to switch to the GraphQL Js schema way
You can find some example in Parse Server GraphQL tests at the end of the file.