You can write a note but honestly im not sure how much it will help. The mind is powerful, think about how many of us here, we probably have people telling us things arent as hopeless as they seem, and we arent as useless as we think, and they are probably right. That is not to say there is no truth to our suffering, but at least for myself its hard envisioning anything positive and worthwhile about myself even when it is staring myself in the face. I find a way to trivialize or ignore it. It is probably the same with loved ones who are left behind. You could probably make a note or video excusing them from blame, insisting its not their fault and there is nothing they could have done, but their minds will likely ignore that and they will stubbornly believe its their fault and they will be full of guilt. I know the scenario i mention here doesnt apply to all of us, so I humbly mean no offense to anyone here.