Sorry if I am missing the point but what is the basis for your claim?
What consideration did your son provide for the ticket?
Have I got this right? Basically he sold a ticket offered to your son and so you had to purchase it?
No, I'm afraid not.
This is a broken promise but not a breach of contract.
Come what may, your son provided no consideration for the ticket so his friend was legally free to sell it if he choose.
If he had paid for it then that would be different. If he had compensated in anyway that would be different.
This is just plain not a breach of contract and so you have no claim I'm afraid.
Can I clarify anything for you?
Not all promises amount to contracts I'm afraid.
No, not really. It would have done if the payment had been completed but it was not.
You could argue that there was an offer was made but he was entitled to retreat from it and anyway there has been no payment so there is no loss arising from that specific breach.