Adult Diagnosis Process

Today my husband had an appointment with the GP to make a referral for an autism assessment. My husband discussed with the doctor why he thinks he may have autism and why he would like to be referred. The doctor told my husband that he would need to attend around 6 counselling sessions. The program is called IAPT (Improving Access to Psychological Therapies). Which is aimed at people who suffer with depression, stress and anxiety. The doctor stated that my husband wouldn’t be able to be referred for a diagnosis unless he attends these counselling sessions.  

Is it normal practice for patients with suspected autism to be referred for counselling sessions prior to being referred for an autism diagnosis?