Peach Wookie, do you have a hospice organization in your area? They are very helpful with all kinds of senior care issues, not just end-of-life issues, and their services are FREE. Their social workers know all the ins and outs of end of life care. They can help with all the paperwork ; it's very important to get all the paperwork "ducks in a row," as it were. There are legal issues with medical care that must be sorted out, so having a serious one-on-talk with her doctors about the family's concerns is of the utmost importance. If she has no DNR, the hospital is legally obligated to do everything required to save her, unless she is already terminal or not likely to survive the procedure. I'm assuming that your dad has power of attorney?
When my dad died this August, Mom was still taken by surprise, even though we'd been told several months before that he wouldn't make it more than a year or two. Mom only had his internal defibrillator turned off just a couple of months before he died and it was an extremely hard decision for her, even though he had terminal heart-disease, advanced Alzheimer's and terminal cancer.
HospiceAustin sent a social worker to help Mom learn about all the options, helped her find a good nursing home for him, helped her with all the DNR paperwork and even mailed us a packet on funeral costs and how to avoid being over-charged.