Yes, if the child opens up and is comfortable with the counsellor, then child counselling does work. There might be times when the counsellor asks parents or family members to inculcate some change in themselves, following the guidelines of counsellor helps to enhance the process of counselling.
If at any point you or your child feel that counselling is not working or the counsellor is not a good fit for the current issue, then you have a right as client to terminate the sessions, discuss it with the current counsellor or take your child to another counsellor.