You're doing the right thing in being honest with your DS. It's gonna hit him now or later and it's good that he's expressing his emotions instead of bottling them up. My Dsis took about 6 months after my DGF died when she was about 10 to show emotion and when she did, my parents got scared, but dealt with it until she was ok.
When he cries about his friends, remind him that he can still visit them and they can come to your new house, assuming that is what happens, to visit him. You and I know that once he gets settled and makes new friends, at his age, he'll forget about missing his old friends.
You also did a good thing in explaining what is missing of his from home. Better that he is prepared than to look in the back yard to just see a mud pit that took away all his toys and such.
Another thing, you sound like me, wanting to take care of everything on your own without assistance. Get over that and accept what is offered to you by the agencies and govt. You paid your taxes and are every bit as entitled to receive aid as someone who has led a less fortunate life. Right now, you and they are in the same boat. Just be happy that you have support from your family (exclusive of ILs if they are still being goofballs.) Many people have only themselves on which they can rely. You've been making lemonade out of the lemons you've been handed. Take the breaks you need to cry and feel sad, but realize that you are luckier than most.
If you need to listen to a motivational speaker, listen to Randy Pausch on
youtube. There was a thread started about him yesterday.
http://www.disboards.com/showthread.php?t=1857611 He has terminal cancer and has the most positive attitude of anyone I've ever seen. When you think about him, and what he's going through, vs. you and your issues, you will feel like your load is lighter. He asks the question, are you a Tigger or an Eeyore? Only you can decide this, but to me, you sound like a Tigger.