Coolant Change

My neighbor called me to ask if I knew where the Radiator Drain Petcock was on his 1994 Buick Park Avenue Ultra. Being a smarty-pants I said on the bottom of the radiator. But I promised him I would try to find a picture but no luck. Would someone be able to tell me if it is on the left or right side of the radiator. Can it be reached from above or will he have to get down underneath the car? He is in his 80's so I try to help him out. He has never changed or had the coolant changed so he thought it might be due for one. What precipitated this was a lack of cool air in the cabin-I will check out the A/C pressure with gauges (assuming I find the valves).

driver side, bottom of radiator, accessable from the ground.

I had to drop the shield to get to the petcock. I made a socket to fit the wings on the petcock by cutting a notch in an old 9/16 socket. It's too tight to get a plier or chanel-lock in there but as stubby ratchet and socket fits well.