( This tanong is from my dad ) right, He imagrated from Italy to England five years nakaraan and he didnt know that he had to register at the aire!!!

My dad imagrated from Italy the the UK five years nakaraan and he didnt know that he had to register at the aire! A friend of his told him that he had to register now, so he really doesnt know what to do, can you please help :( I would really appreaciate it!!!!