the excellent physician and his sick children

well how profound this parable is.
this parable depicts that shakayamuni's life is eternal but he used his death as an expedient mean to teach his followers. if he will always be there then his follower will take him for granted.
secondly it also states that though shakyamuni has prepared an elixir of life as a lotus sutra but we in the later stage of the law are keep on refusing it because of our own ignorance.
father returning later can be taken as coming of nichiren daishonin at the start of late day of the law with five characters of nam myoho renge kyo.
but children/people refused to listen to him and hence he left Dai-Gohonzon for all so that even after his passing away everyone can be benefitted from that great medicine of NMHRK