I sympathize for both you and the employee. True, the Canadian Human Rights Code does ban age discrimination. But the best way to approach this is as a question of performance rather than age. Specifically, if you can document that the employee isn’t performing up to legitimate expectations, you can take appropriate disciplinary and termination actions the way you would with any other employee who’s underperforming REGARDLESS OF AGE, race, sex, religion, etc. The key thing is being able to document that: 

1. You have clear and objective performance standards;
2. You communicate those standards to all employees, including the gentleman in this case; 
3. You apply those standards consistently to all employees regardless of age, etc.
4. Importantly, you give the employee adequate warning, including the possibility of termination, support and an opportunity to improve, which again should be based on objective, measurable and age-neutral standards;
5. The employee has failed to achieve the necessary improvement despite your warnings and support.

More immediate action may be OK if the situation is urgent, e.g., the position is crucial and the employee’s performance is utterly egregious. BUT IN NO WAY WHATSOEVER SHOULD YOUR DETERMINATIONS AND CONCLUSIONS ABOUT THE EMPLOYEE’S ABILITIES BE BASED ON HIS AGE. If age is even one factor in your decision making, you can be found liable for discrimination. So again, focus purely on performance and not age. Hope that helps and good luck to all involved. Glenn