Sorry about the loss of your son. I did put the whistle on my Harley. Don't know if it works, but why take a chance? We lived about 3 miles from a large metropark and the deer are there by the hundreds. The nature lovers won't let any hunters thin out the herds.
I've hit 4 and my wife has hit 3. They've either been hit straight on, or run smack into the side of my van. (I admonished my wife for swearing in front of the children on that one)
Shorlty after we built our house, I heard a noise outside at night and then 20 minutes later noticed flashing lights in the dark. I took a walk down the road to the corner and found the State police there pulling a car out of the ditch. The ambulance had left a while before. Apparently, two cars had been traveling down the road in opposite directions toward each other. This is parallel to the high speed test track at the GM proving grounds. A deer had run out (from the proving grounds) and was hit by one car. The deer was deflected up and into the lane of the other car where it then went throught the windshield, decapitating the driver. Ugh.
At this time neither myself or my wife had ever hit a deer. All 7 have been after that. We've come not to like them so much.