You can’t legally continue a CAT2 approach below DA/DH unless you have the required visual references. You are not permitted to start the approach (descend below 1000ft RA) unless you have the required RVR.
The aircraft will do it but it’s not legal or sensible due to the increased risk of an accident.
Assuming the RVR allows it you can fly down to the CAT2 DA/DH, if nothing seen fly a missed approach, or if you have the required visual references continue for an auto land.
If the RVR is less than the CAT2 limit (usually about 300/125/75) then you are not permitted to descend below 1000ft RA on the approach.
I hope that makes sense?
LD