Usage patterns
〈人〉が母国に帰るfor someone to return to their home country
He returned to his home country for the first time in ten years.
〈人〉が母国を離れるfor someone to leave their home country
She left her home country and lives abroad for work.
母国のために〈動詞〉to do something for one's home country
The athletes gave their all for their home country.