How 'bout Sugar LiveCD or LiveUSB (Sugar-on-a-stick).
Chat has had a rocky road on SoaS but appears to be on a roll now.
These are suppose to be available through on-disk.com now (or soon) for low media and copying cost.
Frogger: SoaS (Sugar-on-a Stick) is Sugar on a USB drive that runs entirely from the USB drive.
. Then you and your grandson could both be running "XO Chat"