EVA You should also write a separate note saying you are happy to have your son back, he's obviously been well looked after and he's talking about going again. It should be separate from you sons letter. You would probably already have thought of doing that anyway I'm sure.
The chap who runs the bulletin board I linked to earlier in this thread is a USA-Japan exchanger and also into Kendo.
On a related but unconnected note.
Around 2 years ago we had a Swedish student stay in our home on a rotary exchange for 8 months. She was in the disrtict for 12 months but spent some time with other families.
It was a real tear jerking moment putting her on the plane to go home.
Anyhow... she emailed a few weeks ago and asked if she could come and stay again for summer her holidays.
I drove to Melbourne (2.5 hour drive) and picked her up at the airport last night.
The trip home went well and we chatted about school and home etc.
20 mins from home the car died. (an electrical problem)

!!!!!
I had to phone a friend to rescue us and drive us into town.
So....... bit of an adventure.