Trouble is - there are thousands of kids out there, whether stage school trained or not, who are equally or much more talented than Callum.
The whole problem for Callum is that he's been lauded by the judges as being something really special, and unfortunately he's simply not mature enough to deal with that kind of praise from people who are "meant" to know what they are talking about.
I think that Piers suggesting that he will be the lead in a West End musical in years to come is totally out of order. Maybe he will, but on the other hand - he's entering an incredibly competitive business, and it's not simply about being 'cute', having a big smile and being able to sing and dance and not bump into the furniture (or the guy in the bear costume...) at the same time. It's also about luck, being in the right place, being the right shape, height etc etc. and having a huge amount of talent. Piers could say the same thing to thousands of other good kid performers - and they are certainly not all going to get the lead roles in big musicals. Some may well get roles in the chorus in the West End or as another poster said they will be performing in small venues in pantomime, or not at all.
So - Piers' kind of comment just leads to the child believing they have the ability and talent to reach the dizzy heights, it also gives the parents an unrealistic dream for their child's future. So - if it doesn't come to fruition (which is a more likely scenario), it leads to constant disappointment and a sense of failure. I would hazard a guess that unless Callum does find some big level of success (which IMHO is doubtful), by the time he is 25, he'll be still desperately trawling round auditions, still convinced that he should be a "star" because a panel of judges led him to believe it was his destiny. He may well feel that he has failed his parents and everyone round him.
I've seen it happen, and it's sad.