ACAV8R
If Cat 3 had been downgraded to Cat 1 because of equipment failure, AND the aircraft is inside the FAF, the p-i-c is allowed to continue the approach. Look-see is allowed on any Cat 1 approach. Providing he has "adequate visual cues" to safely accomplish the landing, that is allowed. The aircraft doesn't know the difference, it just locks on and keeps on going. IF, however, the ILS LOC & GS had failed, that would be grounds for an immediate go-around. Sounds to me like the skipper made a good call. That's why he/she makes the big bucks.