Take the labels and prices boxes etc off them. I.e. if he has a camera for you get him to test it, take one or two pics so its "his", its unlikey but you know yourself, some customs officer could ruin your day. Without tags etc cant see how they could prove that they are presents.
if he takes the tags off bring receipts with him
if you can't prove the value/purchase price you paid they will charge vat on the items price in ireland not in the country of pruchase
i.e Cannon camera in USA $100 so VAT would be approx 21 if stopped with receipt if no receipt and camer on sale in ireland then vat would be 42