Im so sorry to hear your news Tony.
We arrived here in dec 2006 with a 17 year old boy, a 4 year old girl and had to leave our two eldest girls in Kent. My son didn't settle at all, and like many teenagers found it hard in unfamiliar surroundings with no friends. All he wanted for his 18th birthday was a ticket back home.
Well after going to year12 and meeting friends it started to get easier and he finally found his way and joined the Airforce here. He loves the life, and although he is stationed in Victoria we still get to see him often.
We miss our girls terribly, and since being here they have each had thier own children. I guess it's part of being a parent knowing that one day your children will find other things to do and rely less on you.
It's a shame they can't wait for the 2 years that will allow you all to gain citizenship, then it would be a whole new ball game.
I really, really wish you all the very best and hope things turn out well for the family.