If an employee is terminated with cause, can we terminate his benefits immediately?

Thank you for your question. If you have cause to terminate an employee, you have no further obligations to him/her, including benefit continuation. However, I would strongly recommend that you speak to a lawyer prior to terminating an employee for cause (without even his/her minimum entitlements under the Ontario Employment Standards Act), as there is a very high threshold that an employer must meet in order to do so legally.