Your input into his dx is only to show that his traits were apparent from an early age and to give a general overview of daily life. The rest is down to him and the professionals assessing him know exactly what they are looking for, but as he's a teen he'll not take any of that on board.
Dripfeed loads and loads of info about how Different is Not Wrong.
Some firms actively recruit autistic people as they have jobs that require attention to detail at a level that most NT people don't do well enough.
Computers all do the same thing but Mac and Windows use different operating systems to do that.
Communication difficulties are one of the criteria for autism diagnosis so counselling/CBT/talking therapies, unless done by someone who specifically knows how to present that for an autistic person, isn't a great idea.
Try and introduce more flexible thinking, more than two outcomes for a problem, it is hard and it takes ages, but the more black and white his thinking stays, the harder time he's going to have coping in the world.
Read and watch loads of youtube videos yourself about autism and made by people with autism, see if anything you pick up directly relates to him.
Chats about things that are bothering kids can be easier if done when you are both in the car, sat side by side you immediately reduce the pressure of direct face to face communication.
Right now, he's in shock, he's always thought he was ordinary, maybe individual or quirky, - don't we all - but now it's been confirmed he's "different" Teens only ever want to be one of the crowd, so it's not a great time for him to process the diagnosis, but he'll get there. 