Great that he's getting into it.
I used to compete in powerlifting and then weightlifting (not very good mind, just enjoyed it).
I helped friends who competed at nationals (and one who went to worlds) with their technique though, and coached a few people briefly.
Everyone asked me because my form was good.
I learnt everything from: books, youtube and (obsessively) watching the best lifters.
I only had some coaching when I did weightlifting, some of it was good (and some of it was bad actually).
If he is smart, he should be fine.
You can end up with very good form those resources and you can end up with really crap form while having even better resources available. I think the information available now is pretty good.
I would ask him what he's doing about learning technique and what he thinks is important and see what he says.
Most people have no interest in getting injured and are actually a bit too cautious in my experience.
You might just have to trust his judgement.
One thing people don't realise is technique changes as you get stronger. You have to constantly work on it. The way you lift light weights is different to lifting heavy weights, and that's different again to lifting very heavy weights. Some principles remain the same, but you don't learn it once in an hour, you have to review and adapt the whole time.
How injured can you get? It depends on what you do. In powerlifting and weightlifting you regularly attempt to lift the most weight you possibly can. You will pick up injuries no matter how well you do it. The same for any sport in my opinion.
On the other hand if you take a more moderate approach the risk will be lower. I've had many friends who train for physique or other reasons and are very cautious over getting injured.
I would say your spine is the number one thing to look after. You don't want a disc herniation.
Then your knees and shoulders.
Then strength imbalances can cause long term issues and can be very subtle.
(I actually didn't realise a lot of things about my own shoulders until I started climbing - and in retrospect I could have done some really useful stuff back then if I'd know what I know now.)
I think going to a local club is a great suggestion and would be helpful.
Its worth mentioning some PL federations are not drug tested in the UK, and I wouldn't want to unwittingly take my son to train at a gym affiliated with those federations without a solid grounding in the sport already and a very screwed on head.
GBPF and BDFPA are the two big drug free / drug tested PL federations, and BWLA is the WL one - so I would choose a club affiliated with one of those federations.
Whereabouts are you based? I might be able to recomend a gym / coach.
How can you tell between a fake and someone good?
A good question - look at who they coach, their track record and their qualifications. Strength athletes can be very dismissive of Personal Trainers, but some of them are good.
As an example here is someone I would absolutely trust and recommend - Marc Keys owner of
https://www.facebook.com/castironstr/He did a sports science degree
He's a good powerlifter himself
He's coached proper athletes in other sports (rugby players)
He puts the well being of anyone he coaches first.
If your son went to his gym and explained his situation, he would take him through the basics and look after him without pushing any agenda (like PT sessions, or joining his gym etc)
That's a pretty high bar!
You can tell your son now though, having massive quads is on balance shit for climbing :lol.