It seems your siblings are more than happy to dump all responsibility for your parents in your lap. This would cause me to significantly discount advice from them. I think you need to follow your heart and return to Australia. I’ll also voice the personal view that it is unfair for elderly parents to ‘force’ a child to tear up his life and move back with them. You are the one who needs to forge a happy and successful future. Your mother can move with you to Australia where your sister can assist you in supporting her. That is a far more equitable solution for all. A new location, away from constant reminders of your father, may help your mother emotionally.