First of all, I'm glad your friend is trying to seek help. The online tests are a first step, but your friend should meet with his primary care doctor. Family Doctors have medically sound surveys patients can take (I forget the specific names, but they are quick tests that can be taken during an office visit). These surveys are generally based on the DSM
-IV criteria for clinical depression. Usually, family doctors have a low threshold to start antidepressants for patients who are identified with depression.
As far as flying... your friend should probably seek counseling if they want to make a career in the aviation industry. As far as I know and as far as the current FAA regs go, the moment a pilot is placed on ANY medication that has an indication for clinical depression, they cannot fly. Simple, end of story. Even if a patient is on an antidepressant for smoking cessation, obesity, or pain (bupropion is marketed as Zyban for smoking cessation and Wellbutrin for Depression & Prozac has been used with limited success as an adjunct for obesity treatment & tri-cyclic anti-depressants are used as adjuncts for chronic pain therapy). I believe that all medical certificates are revoked while a pilot is on any of these classes of medications. IIRC, you have to be off meds and symptom free for 3 months (or 90 days?) before you can get your certificate back.
Counseling, especially with a Psychiatrist, cannot be reported to the FAA and as such, should be the treatment modality that your friend should probably initiate to remain a pilot. According to national insurance laws, employers are not allowed to know about their employees medical illnesses.
But I am certainly not the aurthoriy on this. Have your friend get an appointment with an FAA AME (Aviation Medical Examiner). An AME is up on all the regs and is the one who issues the fligth certificates.
Best of luck to your friend for his aviation career.
You land a million planes safely, then you have one little mid-air and you never hear the end of it - Pushing Tin