Please can you give me information on how to get from Terminal 1 to the
TGV station at Paris Charles de Gualle airport.  This is for my son
who is travelling alone for the first time tomorrw morning.

Hello.

The TGV station is in Terminal #2. 
Your son should take the RED shuttle bus from Terminal #1 to Terminal
#2.

sources:

"After clearing Customs, proceed with luggage to the lower level
(boutique level), Door #36 and take the red shuttle (#1) to Charles de
Gaulle railway station. Check in at counter 11, 'TGV'AIR' to receive
boarding documents. Validate your train coupon at the orange machines
before boarding."
source: united airlines
http://www.ual.com/page/article/0,1360,1125,00.html

"Connections between the CDG 1 and 2 Terminals...
 Connections between the Terminals every 7 minutes - Free - Red
Shuttle"
Source: cityorganiser.com
http://www.cityorganiser.com/Paris/getting_around/paris_charles_airport.htm

"The TGV station, located in Terminal 2 of Roissy-CDG airport provides
for quick and easy connections between the train and the aircraft."
source: Aeroports de Paris: Access by TGV
http://www.adp.fr/webadp/a_cont01_an.nsf/$$Affich@ReadForm&cle=X5005205211624491B13FABFF094125687E006DBA25.html

You might consider printing out these maps for your son:

Terminal 1 map
source: Aeroports de Paris
http://www.adp.fr/webadp/a_cont01_an.nsf/0/7BDD334D36C5AB7B4125687E006DC0A3/$File/cdggrand.gif

Terminal 2 Map
source: Aeroports de Paris
http://www.adp.fr/webadp/a_cont01_an.nsf/0/624491B13FABFF094125687E006DBA25/$File/plan%20cdg2.gif


search strategy: "charles de gaulle", "terminal 1", "terminal 2", tgv,
shuttle

I hope this helps.  Bon voyage!