My question involves guardianship in the State of: California
Background: I am a U.S. service member and my wife is a Greek citizen. She has a 12-year-old sister currently living in Greece with her mother. Her mother was recently diagnosed with cancer. My wife and I are her only relatives. Her mother has hired a Greek lawyer to grant us guardianship of her sister.
Question: Will the U.S. courts accept the Greek guardianship or will I need to hire a stateside attorney? Once we do have guardianship, will I just need to fill out a DS-160 for non-immagrant visa?
Thank you very much for your time and help.

