Advice and direction needed assisting elderly parents: Should I pursue DPOA?

I'm 57 yrs. old and have been on SSDI 10+ yrs. due to back/neck surgery problems, depression, anxiety, and fibromyalgia. Moved in with 79 yr. old parents last year to help my mom take care of my dad (and take care of her too). My dad has unrespectable HCC. The cancer and/or treatments has caused among other things his kidneys to begin to fail, edema in his legs, blood pressure to sky rocket. Six months after I arrived he had a stroke, also probably due to cancer and/or treatments. He was on the floor unable to get up over 2 hours because my mom and I were asleep and didn't hear him...my mom is also deaf only wearing hearing aids during the daytime.

I now usually stay awake all night until I hear one of them get up around 7 am & I try to be up no later than 11. My sister and I have become concerned with our mom’s forgetfulness along with her stress level as she has heart palpitations. A home health care nurse comes once a week for my dad and the company she works for hired my mom as his home care/homemaker caregiver; however, she looks at it like finally getting paid to do what she's always done and really isn't active with his medical care & treatments from his 8 doctors. She drops him off at appointments and goes shopping and feels like that's enough. My dad doesn't ask questions because he says they're doctors and know what they're doing plus he's the type that doesn't want to rock the boat and has never even gotten a second opinion on his diagnosis or treatments. My mom gets onto me when I express someone needs to ask doctors more questions. She says it doesn't matter & won't do anything cause there's no cure. I understand there's no cure, but, as a Vietnam veteran that went to work for the government which caused the cancer he's dying from, he has been and going through enough. He shouldn't have to carry this load alone and deal with pharmacies and doctors using wrong codes and phone calls with insurance and paying out of pocket just to not have to deal with it. After setting up and gaining access to his medical records online with his permission I found a huge discrepancy. One hospital noted he did not have a DNR and another hospital noted he did have a DNR! I find this outrageous and it needs to be fixed immediately, in my opinion, and the only way it will be fixed is if I do it and I don't know how I'm supposed to do this. If I have DPOA can I fix this? As far as I know my mom doesn't have a living will/advance care directive and has resisted even talking to me about getting one. I've printed out numerous sets of simple questions to be answered and asked her to just answer a few at a time and she just sets them aside and says she gets too overwhelmed to do it. She has an old will from the 1970s with my biological dad that was never changed when they divorced or since he has passed. I get extremely overwhelmed all the time as nothing I do ever seems right with my mom, she's very set in her ways and extremely overbearing. I've been thinking maybe I should stress to them to give me DPOA for financial and medical, set up and put house & vehicles in a trust with me as trustee, bank accounts set up as POD or add me to them, get papers for living will/advance care directive/end of life printed out for them to sign. They both want to be cremated but that still has to be arranged and paid for somehow. I can't get them to do any of this but I know if I can get all the paperwork filled out/ready and all they have to do is sign them they'll do it no problem. But can I do this without DPOA? Is that the first step then I can do the rest? I'd really like to do as much of the paperwork as I can myself without having to pay a lawyer. How can I find and know if online site for legal papers that I need is legit? Can I use Rocket Lawyer? I need some advice and help to be pointed in the right direction before something happens to them or before I end up having a stroke. Thanks for letting me vent a little!