posh It's a bugger but this lot prove you can get on with life in spite of it. I do have some experience of a friends illness and how her DCs coped which might help. Her 9 year old, undoubtedly found her final illness very hard, and was traumatised at the time, BUT we kept life as normal as possible, and provided plenty of opportunities to deal with it in her own way (children don't deal with these things in the way society dictates, so it comes out in different ways at different times, and you have to be careful not to have any expectations of how they "should" be reacting, we were lucky we had the support of a charity, the rainbow trust, who advised us on the best way to handle things) and she now says 15 years on that it is important to her that she was there for every last minute she could spend with her mother. Her brother even more so cherishes every memory, he was much younger and though he now a very sporty laddy lad IYSWIM he is quite open about talking about his emotions in relation to losing his mum (DDs tease him that he uses it to enhance his status as a babe magnet 
) We have lost two close friends and so know two sets of children who have experienced that trauma, the other children were 12 and 10 and I would say that in both cases, though awful to see them put through it at the time, it has in the long run made them stronger and more resilient, and they are all achievers.
In the case of the 12 and 10 year olds I was absolutely in admiration of the Head and Deputy Head of their private Day/Boarding School (don't want to out too much) who were quite exceptional in the way that they stepped into the role of father figure, encouraging them and building their esteem. However even though the DCs loved school, when offered a chance to board there they refused because they did not want to leave the family home, the memories were too important to them. I have acted as a Guardian to a few expat DCs at Boarding Schools and sadly I do not think you would be sure to find that sort of exceptional pastoral care everywhere. The 9 year olds school made a fuss and picked her out for special sympathy and she absolutely hated that.
However at the end of the day there are certainly some DCs who thrive at the right Boarding School, and only you can know which your son is . I am absolutely sure it would not have been right for either of my DDs .
I hope this helps.
Ash Yes those medical letters are horrible. As I have moved around I have had a few referral letters written and each time it rakes it all up, especially as even now they insist on saying I am in remission which seems very unfair because my chances of dying of BC are actually less than the average woman. I had one lymph node involved, which really pissed me off at the time because it meant chemo but maybe that wasn't such a bad thing? I have friends who had 7 involved and have had no recurrence.
gigs Will be here for all stages of bionification, just make sure the lego is Star Wars, or do they do a soft rock anthem lego? Ha! Of course they do en.wikipedia.org/wiki/File:Lego_Rock_Band.jpg
I found some of the comedy audio cds quite good, Fawlty Towers is still very funny even without the physical comedy, in fact makes you realise how sharp the dialogue is.
NJ I was quite worried that I didn't get paranoid and depressed when my chemo finished, as all my friends hit a wall but then the joys of Tamoxifen awaited.
smee Welcome back from up the jungle, we were hopeless at the guessing game
Barcelona was great fun. Dh was compete dick at times but also fun at others. I have the gorgeous breakfast croissants with chocolate and candied orange peel for the trolley as well as loads of Cava for when it is 
O clock ... but this has turned into a marathon post and I'm sure everyone is asleep......