green card; one year period;

  1. C

    Green card resident since date vs departure date

    I got my dad's green card renewed and the resident since date is June 23 2018. He left USA on April 9th of 2018( i sent his renewed green card to him). Does the 1 year period (by the time he has to return ) start on April 9 2018 or June 23 2018.