I take it this is a 2008 return. He is resident if he has spent 183 days in the 2008 year inside Ireland, or 280 days in the 2007-8 period. He should be allowed full Irish tax credits, and the non-resident sections would not apply.
If your friend was resident in ireland for 2005-7 also, he would be "ordinarily resident" and liable to tax on world-wide income.
You do not mention his married / single status, as there could be other considerations if he is married.