Just to add to this.
A designers job is to design for content and design to make what they are creating successful.
I would start with informing the designer of the intended goals of the site. Then have a discussion around how they feel the current design they have created is accomplishing that.
If there are any holes in the design accomplishing those goals - then a discussion can take place on how strategy, content and design can come together.
The key is to help your designer understand this and lead the team to success.
If none of that works, talk to the owner and pull rank on the designer. Clients speak and think in terms of results - so make your case.
All you can do is provide thought leadership, fight for what you believe in and don't get pushed around or marginalized for common sense recommendations.
If no one wants to listen, you've just found a client not worth working for.
(But remember, it is your thought leadership and sensitivity to everyone's role that makes or breaks it, whether it be the owner, designer, developer, etc.)
Good luck!
