Without knowing on what basis the ee is claiming religious and disability discrimination, it's really not possible to advise you of any specifics.
What I can tell you is that you need legal representation immediately, since the ee has retained counsel. And you need an attorney specializing in employment law who represents employers in this type of situation. This is not a do-it-yourself project.
Since the ee went to an attorney and not directly to the EEOC or your State's equal rights divison, what you can anticipate is that the ee/attorney are looking for you to put a monetary offer on the table to make them go away - assuming no wrongdoing on the part of the employer, that's the usual ploy. You need to obtain legal counsel to advise you on the strength of the claim this ee is mkaing and what the legal issues are. Personally, I'm in favor of fighting bogus claims but that's a call you'll have to make after you seek legal counsel and determine what's in the best interests of your business.
