I don't have the answers to your specific questions, and the whirlwind I am in is different from yours. But I have gone through a lot of my own psychological problems and helped many people through theirs.
The most important thing I can reassure you of is that your emotions are *never wrong*. Facts can be wrong, but feelings just *are*, without being right or wrong. You're going to be going through a grieving process, which includes denial, anger, guilt, plain old sadness, and moments of peace that will eventually grow longer and longer in duration. Don't be surprised if you feel all of these things at once -- this is totally normal when you're hit with so much life-changing pain. A lot of people still believe in the "Five Stages of Grief", which sort of says, "well, you will be in denial for x number of days, then progress to the anger phase for x number of weeks", etc. But it turns out that the psychologist who pioneered that theory, Elizabeth Kubler-Ross, revised it later in her life to acknowledge that the many emotions of grief can happen all at once, or in any order, fast or slow. You may be grieving for your father's struggles, your mother's pain, and for the rest of your family, in addition to your own grief. No wonder you feel like everything is falling apart!
And what's extra weird is that you're having all of these grief emotions, but no one has died... Many people only ever experience grief in the context of death. If you want to do some reading, look into the concept of "ambiguous loss". That has helped me a lot, in many different contexts.
I have so much sympathy for you and I wish you and your family the best of wishes. Please don't hesitate to pm (private message) me any time.