Depends how long there is left to run on the contract.
Should your nephew have more than 11 months on the contract term then he will be charged a term fee equivalent to the monthly charge multiplied by the number of months left, this is going to give a min term fee of £385
If he is more than 9 months into the contract, then your nephew can downgrade his tariff by one price point per month, eg:
Month 10 £35 to £30
Month 11 £30 to £25
Month 12 £25 to £20
£20 is the lowest tariff charge he can get for the duration of the contract, and that would still leave him with a term fee of £120.00.
To downgrade his tariff he will need to contact customer services, and to terminate his contract he needs to give 30 days written notice either by post to:
o2 Disconnections
PO Box 242
Houghton Regis
LU5 5WA
or by email to:
disconnections242@o2.co m (make sure you use the letter o in o2 otherwise the email does not get delivered)