Obviously he, like myself, is a dual national with 2 citizenships (Irish/British). I'm guessing you're thinking about the EEA Treaty Rights... If so, after the results of McCarthy, he would not be able to rely on his Irish citizenship to help you apply for a visa in the UK. Nor would he be able to rely on his British citizenship in Ireland for the same. He has not MOVED if he is a citizen of the country in which he lives and works. Moving to another EU country would be an option (e.g. Spain/France); obviously he has to work/be self-employed/be self-sufficient/study etc. Please note that there are different requirements for students/self-sufficient people (i.e. medical insurance). He could then apply under Surinder Singh.
I'm in the same situation and am considering renouncing Irish citizenship and moving to find a job in Dublin. This is a complex area at the moment and it is the only time I've came across when being a dual Irish/British citizen is actually a MAJOR disadvantage.
Best best would be to contact the Law Centre NI (in Belfast and Derry~Londonderry). They have a website which states the relevant details and have a helpline. You call them and they ask a lawyer to call you back with details.
www.lawcentreni.org:
124 Donegall Street
Belfast BT1 2GY
Telephone: 028 9024 4401
Hope this helps.
C