@spaceboy believe me, the old Indonesian quotes said "Semua terjadi karena keadaan tak terduga dan jalan kehidupan. Jika dia kembali, dia akan terus bersama kita di waktu yang tepat. Jika tidak, biarkan waktu memulihkan luka dan keadaan".
English translation:
All of things could happen because of the unexpected situation and the fate. If that person come back to us, he/she will always be with us in the right time. If he/she is not, let the time heal the pain and the situation."
P. S. There always be a good reason for them to be back and to leave this site.