Hmm, never heard that one, but am interested as myself and my good lady set ourselves a challenge last year to visit every inhabited island in the British Isles. By our calculations there are 208 in England, Wales, Scotland and Ireland (north and South). So going to take a couple of years.
If you were to include every island, that would jump to over 6000. So if he were to camp on a new one every night, it would take 16.5 years.