My wife and I ride bikes a lot and love to commute by bike as well. My youngest son rode a bike about 2 times when he was 6. At that time, had a crash and lost all balance and "will" due to complete fear and has not ridden a bike alone since. He is now almost 12. He loves to ride our tandem with me and has ridden the state of Michigan when we went on tour. But, fear keeps him from riding solo.
Last Christmas we bought a new Trek 7.2 FX for him and set it in the kitchen. 2 days ago he spent the evening re-learning to ride with me. Within 24 hours, he rode 21 miles around our neighborhood. Now we can't get him off the bike. We are going to have so much fun. I can't wait to get home tonight and ride with him again.
Overcoming this fear is much more than riding the bike. I hope it carries him far.