Make an Admin undeletable by other admins

Hi

Basically we are working on a news site together but its in maintenance mode and he is an Editor at this point and so cant actually view the site just his user backend. I just want to give him enough privilege to view the site but not really admin rights to make changes. Admins can delete other admins and I dont really want another admin. Is is possible to make one admin undeletable by other admins?