There is a fundamental problem in the approach to managing young bowlers at present whereby they are not getting conditioned to bowl for an extended period of time.
I think part of the problem is T20, whereby they are warming up, bowling an over or two, cool down, warm up, bowl again, cool down etc. It also doesnt encourage any rhythm in their bowling action as they have to vary delivery stride, point of delivery etc all the time.
Bowling restrictions in juniors are clearly flawed, but then they carry that on in senior cricket whereby they seriously lack net bowling, usually it's half paced etc.
Then when they do bowl in a game suddenly it's 25 overs in a day, then they break down - and they wonder why?
Need to concentrate on
- A very strong core, rather than the muscles that just get big, along with a decent amount of endurance fitness.
- Conditioning via a good action, not a mixed one, and a reasonable amount of bowling
Possible just doing a bit of bowling every day would help, rather than 5 days off/two days excessive bowling as tends to occur.
tl;dr get him the f**k out of short form games and get him conditioned to bowl.
Also he's just in the age where he's vulnerable too stress fractures. Playing him in international cricket seems like madness.