Re: Sad and I don't know what to do....
I would wait to tell him until you know for sure what is going on.
BUT, just to make sure, why don't you go pick up a little web cam, they are really cheap and pretty cool. You can hook it up to your computer, and schedule him a time in to sit down and talk to his friend, ANDyou can get a mic. It would be like being there with him. (the other child have a computer available?)
I agree that you should talk to his teacher. . . .
My oldest son, 10, is friendswith a little guy who suffered a brain tumor as toddler. He has tons of issues that were a result of the surgery to remove it, and has a hard time making friends.. . . My son, who is WONDERFUL, empathetic, and just a GOOD kid, was so good with him. . .for 3 years he was in the same class, sitting next to this boy. I guess my son was able to keep him settled in. . .unfortunately this wasn't the BEST thing for MY son, all the time. The other little boy didn't want him to have other friends. I spoke with the teacher about this, and they were sooo understanding, and had admitted that it was simply easier for them the way things had been. Well, they ended up splitting them up, and the other little boy was able to make other friends, and so was my son. It was a win / win situation.
EVEN, say, if this child was NOT to move. . .perhaps it is good to broaden their friend base a little. It's never healthy, for anyone, to have just one person they can hang out with. . . doesn't really give us that variety in life, huh? New people to learn from, to teach.
I guess that I am rambling, but I think that this is something that can be handled fairly smoothly. . . .
I have YET to deal with it myself with my autistic son, so I can't relate to the true dynamic of it all. . . .. .
BUT, as a mom of children who have moved several times, I do understand the heartache that is involved with MAKING NEW FRIENDS, KEEPING THE OLD, ONE IS SILVER AND THE OTHER GOLD, process! With technology, we can keep touch with anyone we want. No, it's not hte same as sitting down with your best friend, in person. . .but it certainly makes things less yucky.
Maybe, before ANY move is to take place you have them spend some time together making a book or something together. . . putting pictures together, art stuff. . like a little scrap book, something tangible. So that when the time does come, they will always have something of each other. . .