I haven't heard PTSD characterized as a hopeless disorder before. It's horrible and deadly, but time heals, or at least softens, most such wounds. What could have convinced the psychiatrists that this time it was permanent?
We are talking about a teen into 23 with improperly treated mental health issue here. People get treated for decades for this kind of thing, not 5 years of trying mostly new drugs with side effects to paper over it.
While suicide might seem like a cowardly way out to some, there are other sufferers who choose to take their chances with electro-shock therapy, which has experienced rejuvenated interest over the past 20 years. It should be clear, however, that anyone pursuing it has exhausted all over treatment and is still suffering to some great extent.