That is an awful lot of boat to hand the keys over to, but at the same time, its a fishing boat, and if he's only taking one or 2 other friends, planning on fishing, knows the 'rules' of boating, and is otherwise responsible, I think you'll be ok.

Just to relate some personal experience. My father was never a boater, heloved to hunt and fish the creeks and rivers, but never owned a boat. I have personallyowned one boat or another since I turned 18. I never had the advantage of having an experienced boater to show me the ropes. I pretty much learned everything on the fly, on my own. My first trip to the launch I wont soon forget. Through all that, I never managed to damage anything, and myself and my friends who have been out with me all survived. If your son has a level head he'll be alright.