I'm a firm believer in strategy and UX as products of the intersection between business needs and user needs. People don't use a brand or a product just because you want them to. They use things and ideas that advance their own goals. A smart company doesn't look for problems that fit its solutions; it designs solutions to existing problems.
This applies to your website as much as it does to your core product/service offering. A website that gets in their way (instead of being intuitive) gets abandoned if other low-barrier options exist.
If your boss is analytics-driven, put that to work in your favor:
1. Test the site design and walk him through the test results.
2. Have him observe paper or online testing in a lab environment so he can witness the frustration.
3. Give him concrete examples of user frustration & abandonment caused by business-centric design; solicit his own frustrating experiences to generate empathy.
4. If you have an A/B or multivariate test platform, put it to use on nav variants and report back with results. Google Web Optimizer is free...
5. You might consider a SWOT or other type of competitive analysis to evaluate the real cost of abandonment to the business; it's hard for me to comment on this in detail as I don't know what your company does or how it's positioned.