Is there an application that can check for broken aliases in Finder?
File Buddy might solve your problem. According to their website, it can:


  Find empty files and folders, orphaned files, duplicate files, broken aliases, and unused preference files.


The user interface is a little weird, but it does have the functionality to scan either the entire drive or a particular folder, so I think it'll meet your needs.

It costs $39.95, but you can give it a try for 30 days/10 launches for free and see if it works for your situation.