good on him for deciding to give up!

i would suggest cutting down before quitting, i wont go too much into it, but i have been in a similar situation myself, and when trying to quit, it sent me loopy(what i mean is, i tried to stop for a few days, then had some, and i ended p curled up on the bed not being able to speak to anyone for about 3 hours.. horrible!) so i just began to cut down, and eventually i was turned off it, because i enjoyed the awake feeling, more than the feeling of being hidden (sorry if that doesnt make sense, its the best way i can explain!)

seeing a doctor is a good idea, i dont know about anti depressants tho. i would never have considered that myself.

nest of luck to him! and keep encouraging him to continue cutting down or quitting, its just like giving up cigarettes, you need support!