If you hold a residency card of a Eu family member in another Eu country can you stay in Ireland using that card without apply again in Ireland

I’m after some help, a very good friend of mine ( he is Irish ) is going to Malta from Thailand with his wife ( Thai ) and they want to bring her son who is 25 years old, they live in the same house and fully dependent on the Irish citizen, I know Malta takes around 6-8 weeks for the RC to come, and...

Has anyone moved to Lisbon Portugal with there non spouse? Was it straight forward and how long did it take to get approved.
Thanks

Out of interest what other Eu countries are friendly to dependent family members ?

My friend told me that he is applying for his wife Irish Citizenship as she has been in Ireland for 3 years and there non EU children, I thought the wife could apply after 3 years and the non EU children have to wait 5 years, could someone please confirm.
Thanks

Hello Everyone,
Been living in Ireland for just over 3 years and thinking about applying for Irish citizenship through association as my great grandparents were born in Ireland, does anyone know how long it takes and if it would be approved?
Thanks
Harry