I agree that this is completely thoughtless as a gift. It's like giving someone else a pet. There are just certain things that those outside the home have no right to do in my opinion.
I have always wanted a motorcycle. Years and years ago when I got my first ride on the back of a friend's bike I returned home to my mother on the front porch with tears in her eyes. She knew. She knew once I had experienced it the first words out of my mouth were going to be "I want one". And she was right.
Coming from England, where bikes are also very common, she had known too many friends that had lost their lives due to motorcycle accidents. The pain in her eyes was too much for me. I never pursued it.
Then after beating my battle with cancer, my first thought was I needed to do something - it was my second chance at life and wanted to grab on to a dream. I told her (and others) at a dinner that I wanted to enroll in class and get my motorcycle license. The pain on her face was still there. She did not try to stop me. But I knew I couldn't go through with it. I couldn't put her through that. I couldn't break her heart.
Talk to him. Be honest. Share your feelings without anger. And perhaps, he will also make the right decision. If not for himself, for you. You might be surprised.