I wonder what I could've done differently, what I can do now and who else is in the same position as I.
Nothing.
Doubt is fear that you have before you act. Regret is fear that you have after the fact. Doubt is useful in that it makes you consider your options, but once you choose to act, it's useless. When you commit to a course of action, doubt must be left behind for second-guessing yourself at that point will only result in an increased chance of mistakes.
Regret is useful in preventing you from repeating a mistake, but there comes a point where you cannot improve anymore. It is regrettable, but sometimes, your best is not good enough and nothing can change that. It is a form of fear that is useful to help us hone our skills, to focus on a failure until it is a weakness no more. But there is a point where it becomes useless and you have to just accept your limitations.
Courage is not the absence of fear, but the ability to act in spite of fear. In the moment, courage allows you to harness your fear. When you are afraid, you are stronger, faster, and more perceptive as time slows down. Properly channeled, fear is a great advantage. Fear comes at you like an ex-lover who knows all your worst secrets. She's painful to have around, but if you can keep things civil, she's got your back. It is far harder to control Fear, but much easier to put the genie back in the bottle when it's over.
When you look back at what happened, and you beat yourself up and never forgive yourself, the only question you should ask is, Would the person I am suffering for wish me to hurt like this?
Which is worse, being at fault for the deaths of the ones you love, or FAILING the ones you love?
Of the two, most people choose to be at fault, because then you could easily punish the one to blame.
But you aren't at fault. There is no way to balance these scales. There is no way to ever have "justice" because life isn't fair.
And that's a good thing.
Because I can make life fair. I can balance these scales with a single sentence.
"THEY HAD IT COMING."
The suffering of your loved ones is made fair if they were bad people who deserved it. However, I can tell you from personal experience, that isn't the case. The world isn't fair. Good things happen to bad people, and bad things to good. Something bad happening doesn't make you a bad person. When people want life to be "fair", they often just wish for life to be unfair IN THEIR FAVOR.
I want that too.
I want everyone to live a life most unfair. I want people to win far more than they deserve. What a horrible world this would be if it was fair. Everyone always breaking even. Nobody gets ahead, nobody falls behind. Everyone always arriving at ZERO.
I say cheat.
Get more than you deserve. Help someone else get more than they deserve. You don't have to drag someone else down to get ahead. Everyone can win, but for some reason, we don't believe that. So we have people like those who harmed your brother. They thought they could only get more by taking from someone else. Most people who commit crimes believe this. It is how they justify their actions.
"I'm making life 'fair'."
"I'm just gettng what I deserve."
No. You don't deserve anything, and making life fair never works, because most people don't even understand what "fair" is. Don't make life "fair". Don't even try.
You can start by letting go and allowing yourself to win, even if you don't feel you deserve it.
Because nobody deserves it. Instead, just try to win without hurting anyone else in the process.
Make the world a better place than you found it and the rest will sort itself out.