While writing, don't concern yourself with spelling, grammar, punctuation, being redundant, or making sense. Write half-baked ideas, thoughts, or feelings if you want. The goal is not to write something good or something that will ever be read again. The goal is to write simply for the sake of getting it out of your system. Mourning papers can cover anything complaints, dreams, frustrations, feelings, and so on.
Nothing is too trivial.
Complain about the barking dog next door. Write about your life's dreams or sorrows. Create a grocery list. Unburden yourself of pain, sorrow, fears, and regrets. You can think long-term and create a better life for yourself or you can work on immediate needs.