I've no business commenting on this as I haven't ever suffered a similar sort of trauma, you could argue. However I did start reading this note and found myself strongly flustered at this part:

I thought that if I got into to a good college, or a good grad school, or lost weight, or went to the gym nearly every day for a year, or created programs that millions of people used, or spent a summer or California or New York or published papers that I was proud of, then maybe I would feel some peace and not be constantly haunted and unhappy. But nothing I did made a dent in how depressed I was on a daily basis and nothing was in any way fulfilling.

I'm annoyed at how stupid it is. And how, until recently, I wouldn't even have noticed. Let me translate to illustrate:

I desperately wanted to see what was on top of that hill over there. I thought that if I got into to a good college, or a good grad school, or lost weight, or went to the gym nearly every day for a year, or created programs that millions of people used, or spent a summer or California or New York or published papers that I was proud of, then maybe I would find out what is at the top of the hill. But nothing I did made a dent in my knowledge

Wouldn't that be silly? Wouldn't that make you wonder what he was thinking? Wouldn't you say "so go climb the hill. That's what you need to do and that's all you need to do. Forget the distractions. Go over there. Climb the hill as high as you can and keep trying every few days until you build up the fitness to get to the top".

Yet you see the note of the guy and you feel sorry for him and how hard he tried to keep living and how much he struggled and what pain he was in and he missed this concept completely. If you want peace you need to work on peace and why you can't be at peace and changing yourself so you can. If you want to not be haunted you need to work on not being haunted and if you want to be happy you need to work on being happy and how you can be. Not on grad school or weight loss or gym work or anything else. Your life isn't unhappy, your thoughts are unhappy. Don't improve your life, improve your thoughts. It might not work, but the other way cannot work.

If your code isn't working right, you'll never ever ever fix it by going to the gym. You will only stand any chance of fixing it if you look for the bugs in the code that isn't working and out from there. If you have been hurt and can't be happy, you need to work out how to feel happy even though you got hurt. That's it. That mental adjustment is where the bulk of your energy should be going. Learning to change it and trying repeatedly until you succeed.

It's so frustrating to look at it and see him basically saying "I skirted around my problems all my life and suffered horribly, and when they didn't magically go away I decided they were completely unfixable".

You can feel however you like about whatever you like. This definitely extends to feeling good even when bad things happen. Maybe not all bad things, but many. It may not extend to PTSD. What's frustrating is that he believed he was unfixable without any solid basis for that belief - without talking to a single expert, even - then made the biggest and last decision of his life based on this conclusion.

It's not cowardly or morally inferior or anything like that, it's just ... a strategy that stands a low chance of helping.