Sally sorry that you are having such a quandry regarding your move. I have lived overseas in many different countries with my two boys and can feel your anguish at moving a child with you. I have been down the route of do I homeschool, send them to public school, parochial school, or private school. My two guys both had learning difficulties and so at times it seemed that home schooling may have been the best way to go. As a child my parents immigrated and I so missed my family I decided that they probably needed to have friends to take the place of the missing family, in the long run it worked out for the best, I spent a lot of time looking at the schools that were available and (whilst living in America) found the perfect placement for them. They are now both extremely successful in their adult life and have formed amazing attachments from their school days. It is a matter of finding a comfort level for them, and for you. Check out some of the schools that others have mentioned on this site, I knew I had found the correct place for one of my sons when I went to visit the school and the kids were sculpting amazing statues in the woods outside, probably somewhere I would have liked to have been taught myself. It turned out to be an amazing placement for him, and one I never regreted. My son was always rather quiet and withdrawn and the school and his friends he made from that school bought out the best in him, and have remained in his life for many years. You made this amazing move to make a difference to all your lives, and I am sure that whatever you do will eventually be the right thing. Remember just don't feel guilty and don't blame yourself for everything that happens, unfortunately that is life, and when we make the decisions to take off on these ventures it is easy to do blame yourself for all these things. All these years on my kids loved their life travelling the world and meeting different people and they have grown up to be the most amazing adults, everyone that meets them makes the same comment they are so at ease with themselves, and I am sure that your child will be also and will thank you for the sacrifices you have made for him.
All the best and good luck with your decisions, I look forward to hearing how it transpires.