Can an Ontario court grant relief from the forfeiture rule even where someone caused the death?

In limited circumstances, yes. Ontario courts have shown some flexibility in how strictly the forfeiture rule is applied, rather than treating it as an absolute, one-size-fits-all bar in every case where a person contributed to another's death. Where the death did not involve real moral culpability on the part of the person who would otherwise inherit — for example, some cases involving diminished responsibility or a finding of not criminally responsible on account of mental disorder — courts have been willing to consider whether strict application of the rule would be unjust in that particular case.

This is not a guaranteed exception, and it isn't available simply because a criminal charge was reduced or a person expresses remorse. Courts weigh the specific circumstances carefully, including the nature of any criminal finding, the underlying facts of what happened, and broader public policy concerns about not rewarding wrongdoing. Because this area of law is still developing and highly fact-specific, and because Ontario has no comprehensive statute spelling out when relief is available, anyone in this situation should get legal advice tailored to the specific facts rather than assume how a court will rule.