Did he meet all the rules to do that ? You don't report on tax return. Just keep 1099Q and 5498 for your records

• The 529 account must be at least 15 years old 
• The Roth IRA must be in the same name as the 529 beneficiary
• The amount to be rolled over must have been in the 529 account for at least five years 
• The rollover must be within Roth IRA annual contribution limits
• The rollover must be a trustee-to-trustee transfer
• He must have earned income at least the amount rolled over