The Kalash language is a mix of the languages found in the region- Tajik, uzbek, tartar, persian, etc. But, there are Greek words for woman, washing, winter, greetings etc used among the several Kalash tribes that are Greek. While even that can be explained under the PIE theory, your statement of 'absolutely nothing to do with Greek' does not stand.

But further study- genetic and archeological- is necessary.