I just want to send hugs to your entire family right now.
I have not been in this situation before so don't have a lot of words of wisdom, but wanted to let you know you were heard and what you did appears resonable to me.
Just my two cents, but I often don't have a reaction until later (shock or something). I can see myself reacting in a similar way to your son. For me it usually takes a bit though to work through how I am feeling.
Again hugs and kind thoughts heading your way.