Thats a VPN, if the bookie WHOIS's the IP address your son is using they will see it is a VPN service which screams FRAUD. (why would you be trying to conceal your real address unless you are trying to signup more than once).

I know this is not the case, but you would have a hard time explaining it isn't, especially if you are already signed up to the same bookie.

(I dont know if bookies go into this much detail to rat out fraudsters)