It is very important to understand that the reason suicidal thoughts can take place is because the person is overwhelmed with "stress", and that is what the person wants to discard. PTSD is a "stress breakdown", it doesn't happen because a person is a failure or should feel guilty or that they are a criminal either. It is actually a "normal" reaction to a trauma, or trauma's where an individual was stressed and did not know how or what to do at the time.

All human beings deal with "stress" and have to learn "how to" manage it all their lives.
PTSD is definitely a challenge, but a person "can" learn how to manage it and develop "skills" where that person can actually have many levels of a calm and sense of balance.
With the right help and therapy, a person can learn to review their own history where they experienced stress and just did not have the skills to manage that stress at the time. Each person will be different in their healing time depending on their history of stressors and finally taking the time to work through whatever challenged them in their past. We all have the ability to "learn" to thrive in spite of the challenges we have faced in our lives. Working through PTSD takes time, however, a person really "can" make gains and even have a higher understanding than many others.

Life is about "learning" and we never stop learning and growing all our lives and while there are times where the stress can be a huge challenge, a person can "still" learn and make gains and be proactive.