If anyone is writing with the sole intent to disperse guilt, the suicide note of a mathematician is good place to look for inspiration:
"Until yesterday I had no definite intention of killing myself. But more than a few must have noticed that lately I have been tired both physically and mentally. As to the cause of my suicide, I don't quite understand it myself, but it is not the result of a particular incident, nor of a specific matter. Merely may I say, I am in the frame of mind that I lost confidence in my future. There may be someone to whom my suicide will be troubling or a blow to a certain degree. I sincerely hope that this incident will cast no dark shadow over the future of that person. At any rate, I cannot deny that this is a kind of betrayal, but please excuse it as my last act in my own way, as I have been doing my own way all my life." --Yutaka Taniyama
That being said: Some may find it worthwhile to address the note to specific individuals (since it may well be the case that there are some family members/friends whom are innocent, and others not so much). If ethics/morality is your goal then it may be in the best interest of others that you not only disperse the guilt of the decent/innocent, but also leave a warning to those (who matter to you) of others in the family whom you could see causing problems down the line. Personally, I've taken it upon myself as a final task to point out the negligent/inept financial and parenting behavior of someone in the family, for example. Social dysfunction/flaws can become more obvious in one's final weeks, so this gives one a special perspective on matters such as these. Some may find it worthwhile to simply, clearly, and briefly bring the unethical/immoral behavior to the attention of others, even for the possibility that it may well spare them some future grief or unnecessary trouble, if anything.
