if they are a PADI AOW, they do not need the 20 dives to start.
here is the exact wording from the PADI instructor manual.
To qualify for PADI Rescue Diver
training, an individual must:
1. Be certified as a PADI Advanced
Open Water Diver or
have a qualifying certification
from another training organization.
This is defined as proof
of certification beyond entry
level (at least two certifications
total), and proof of 20 or more
logged dives documenting
experience in deep diving and
underwater navigation.