Always sad.
Long-time rider and firefighter/EMT here...and I have seen scores of accidents like these on exactly this type of road - curvy enough that failure to understand the importance of countersteering will result in not being able to negotiate a curve properly...and you eventually drift out and hit a curb as you fight the steering.
I'm not saying that is what happened here...but it is what happens more often than not in this type of accident. I have actually met folks who have ridden for years and who still don't know how to countersteer...or why they would.
If you ride, you should read this:
http://www.amazon.com/Twist-Wrist-Motorcycle-Roadracers-Handbook/dp/0965045013
...or his updated version:
http://www.amazon.com/Twist-Wrist-Basics-High-Performance-Motorcycle/dp/0965045021/ref=pd_bxgy_b_img_b
And for the folks asking about a helmet - he hit a tree. His body was probably moving 30 to 40 MPH when he hit that tree and he then came to a dead stop. His head could have been encased in stryo peanuts and he wouldn't have likely made it. Your organs are torn apart with such a sudden stop...often with your aorta tearing free from your heart. A helmet and a good thick leather jacket will certainly help, but they aren't doing much to offset blunt force trauma.
RIP buddy...and prayers for your wife and family.