No offence, but if your boss relies heavily on email... he should understand the pros and cons of his choices.
Email blacklisting is a byproduct of spam... and with so much spam out there, companies have began to automate blacklisting.
AOL puts this control in their users hands - which is 100% wrong. A couple of lazy AOL users who don't want an opt-in newsletter anymore ding the spam button instead of unsubscribing... and bang our email servers get blacklisted again.
ISPs of all shapes and sizes have been nailed by that blacklist... call your ISP and get thier SMTP servers (if they offer them for you) and also ask them when the last time AOL BL'ed them.