He will receive the dividends after deduction of Dividend With-holding Tax (DWT) of 20% has been deducted by the company paying the dividend. If his only income other than the dividend is € 12,000 as stated, he will not be liable to any further tax on the dividends and in fact may well qualify for a refund of the DWT.
His tax calculation would be something like the following (using 2008 figures, but 2009 is more or less the same)
Earned Income 12,000
Investment Income 2,200 (this is the gross amount, he actually receive 2,200 less DWT of 440 or 1,760)
Total income 14,200
Tax due @ 20% = 2,840
Less any tax credits
Tax credit (single person) 1,830
PAYE credit 1,830
Actual tax due 0
Tax paid
PAYE 0 (assuming his employer has his correct tax credit and band)
DWT 440
Tax refund due 440
So he can claim a refund for the DWT (dividend Withholding tax) from the revenue. The revenue online system is the easiest way to do this - see this page on revenue site [broken link removed]