She had to.
Everyone was wondering why she missed the second Iowa rally, and news were surfacing that her son had been arrested the night before.
So dammed if you try to explain why, and dammed if you don’t :(
She didn’t have to politicize it.
She should have simply said that her son had a legal situation back home and as we find out more about it and it proceeds through the legal process, more will become publicly known.
She made the PTSD a part of her speech and linked it to the incumbents policies toward soldiers. She put that part of it on the table announcing her support and endorsement of Trump.
She opened the door to the questioning.