No advice on flight packages or anything but I do have experience of being 12years old and flying to Australia alone.
I went with Japan airlines as an 'unaccompanied minor' from when you check in they give you a time to meet them at the security gates, they then escort you through all security and I was taken to the business class lounge, suppose it's their way to keep you safe, then they come back for you to take you onto the flight, then pass you to the air hostess and she will sit you in your seat, check you've got everything - if there are other unaccompanied minors on the flight you tend to all be sat together and to be fair they check on you regularly through the flight,
Then it's a stop down for fuel wherever planned, mine was japan, this time you are the first to be taken off the plane and again escorted to a special lounge and they then come back for you to re-board.
Once you land in Oz, again you are the first off the plane and they take you through security, baggage claim(bags are put on first drop too) and then pass you to whoever is collecting, sign you over to them and that's it!
I did it numerous times and was always very comfortable with it all, at no time felt nervous or anxious because there is always someone there if you need something, however I had done the flight with parents prior to this so it wasn't my fight long haul flight ever.
This was 10 years ago now so I imagine things have changed a bit but probably not too much.
If you think your DS is mature enough for it then I'd say let him go, but he will need to listen to those in charge of him and be able to entertain himself for the flight.
Would recommend Japan and Emirates airlines.
Good luck!