Many years ago I was hit by a pick up truck from behind. Broken back and all that fun stuff. At that time my father told me to never got on a bike again. I was 29 years old. I got on, with a body brace in place, a month and a half after the accident. Dad got over it
It is a knee jerk reaction. Fear, seeing your injured loved one, causes a lot of worry. What if it had been much worse? I was lucky, as that same fall several other riders were hit and died.
He will calm down at some point. If she wants to continue riding, she will.