There are several fundamental claims which may be made against an employer due to a medical disability, apart from human rights remedies.

The termination may be found to be a breach of the duty of good faith and fair dealing, which may lead to an award of aggravated and/or punitive damages. For example, an employer which insisted that the employee return to work, against medical advice received by the employee, would likely give rise to a successful claim of the duty of fairness.

Ontario also allows a civil claim to enforce a human rights obligation when accompanied by a second claim.

If the disability is permanent or serious and caused by the employer's conduct this could lead to a claim by the tort of the intentional infliction of mental suffering, including punitive damages.

These claims are discussed in detail in the site Exceptional Damage Awards.