If you have any questions about whether to fire the employee, the employee has made noises about consulting a lawyer, or your company may have made some mistakes in its handling of the employee, you should absolutely talk to a lawyer before making a final decision. A lawyer can help you make sure you've considered all the angles and done all you can to protect your company from liability. For more information, see Nolo's article When Does an Employer Need an Employment Lawyer?
For legal advice, you'll need to talk to a lawyer.