I'm not a doctor, but, I am diagnosed with PTSD, GAD and SAD. I can be physically triggered, in a verity of ways. Sometimes it is simply heat in my chest. Shaking happens rarely, and only when I become extremely upset by something, and my body responds more intensely to the trigger, than my mind. Although, shaking is a product of the chemical occurances in the brain, at the time. PTSD stays with a person for life, even if dormant for most or all of the person's life. As you likely know, symptoms can be triggered, at anytime, throughout a persons life. Your Mom probably needs more information about PTSD.