Sounds like a poor SCART connection: Try the following in order to determine the problem, going to the next step only if the problem is still there.
1. Check cable is firmly in Digibox and TV
2. Try another SCART cable (making sure this is firmly connected as well)
3. Try plugging the digibox into AV1 instead... if this works, your TV has a faulty AV2 socket which should be fixed.
Hope it works out for your friend
Happy New Year!