Dearest Sorcha, we all take risks in our painfully transient lives, i can well understand anyone being "anti" bike, perhaps because the risk factor of an accident is 30% higher than driving a car.
however, should you talk to most "bikers" they will certainly tell you that the risk is worth it.

I've been a biker for 30+ years with only one accident, which was my own fault and fortunately only dented my pride.

Bikers are a unique breed and in general understand and accept the risks they take for the feeling of "freedom" two wheels gives.

Almost all accidents are caused by bad drivers of cars.

I sympathise unconditionally with your situation and wish you and your son only the very best.