I can't think of a way to do it unless your IP stays static or atleast does not change often. Let me know if you have any other thoughts.
-Corey
in the cpanel for the Remote Database Access Hosts list, he can add hostname not only IP address, isn't he?
Then he should register a dynamic dns at no-ip.org, then install the client, wich automaticly update his ip to the database.
For example the home.ironiq.hu host always pointing to my router at my home, so I dont have to trouble with the dynamic IP-s.
Option 2:
The dynamic ip-s usually taken from a static pool, so the first 2 byte should be static, and you could add a rule, like this:
81.182.%.%
Sechole: Everybody from your ISP are able to connect.
Tyrael