Can an individual be terminated or fired from a job who on temporary disability for job abandonment?

Most states are employment at will states, meaning the employee or the employer has the right to terminate the employment agreement without notice or reason. So yeah they can terminate you for just about anything. Did the person work their long enough to apply for FMLA (Family Medical Leave Act). If so then the employer can't fire them as long as they are on FMLA leave for the temporary disability. Hopefully, they can file for unemployment if they worked their long enough.