Cancellation of the dependant visa in case of cancelling the sponsor visa

Yes, of course.

Otherwise, If you leave the country they will not be able to cancel themselves without your attendance.

Thank you.

Yes, it would be better to cancel them before you leave.

Dear Sir,

As per the rules and regulations, it is mandatory for you to cancel your family's visa- who is/are in under your sponsorship- before your working visa will be cancelled.