Read all the other comments caretaker - notice anything?
You are in a lonely minority in applauding gardenman's overreaction. 
Other members have expressed sympathy and understanding for the sadness he is experiencing at the thought of his children and grandchildren going to Canada, but have also pointed out that they are free to make that decision. This is not the 19th century and they are not off to some distant planet for heaven's sake! I can relate in a way to his scenario though.
My sister, her husband and their 3 very young children (5,4,3) took that plunge in the 60's when flights to Canada were way beyond the reach of working people like my parents. They must have been devastated but knew that this move was the best thing they could have done at the time. From being a humble lab technician in the north of Scotland,( he had dropped out of university when they had their first unplanned baby, and there were no prospects for a young man without qualifications) , my sister's DH was able to study part time, eventually becoming a Professor of Marine Biology and a leading marine biologist advising the Canadian government.
Eventually they were able to afford the occasional visit "home" to Scotland, but only every. 3 years or so. To this day I can remember my stiff upper lipped parents fighting back the tears as we drove to Prestwick when they first left.
The world is much smaller now, we have Skype, emails, FaceTime etc and flights are much more affordable. What saddens me is that OP's principal grouse if that the DGC are being taken away from them. Stop and think.
Whose children are they??
My vote us with all hose who see this as a selfish and harsh response. Sadly also designed to produce exactly the opposite response OP would have wished for.