How can I help mom?

My mom is 82+ years old. She moved in with my husband and myself almost 2 years ago. She was having some problems with mild dementia. My dad died almost 6 years ago and her only reason for going on seemed to have been to care for him. My brother and I became concerned when she called my brother almost 2 years ago to tell him that she could not find my dad and had been looking for him for a few days. She was extremely physically sick when she first moved in but in time she appeared to be more cognizant of her surroundings. It took us almost a year of going back and forth to the hospital to find out that she had a case of severe perforated diverticulitis. This was after other hospitalizations that yielded no clue as to what she was going through. Her recovery has been long. She has lost about 100 pounds in the last 3 years all total. She is becoming paranoid about the doctors and is seriously depressed. She has slowly isolated herself into her bedroom upstairs. She has succeeded in getting a small compact refrigerator, a microwave, toaster, small coffee pot, television, echo and small utility cabinet in her bedroom. The adjoining closet is organized with medical supplies, toilet paper, and paper towel. We have a small bathroom which shares a wall with the end of her closet. She has paid to have that bathroom remodeled. I have a difficult time lately getting her to even come down the chair lift to join us as a family. She prefers to remain in her room. When I try to speak to her about her increasing isolation she just says she is sick or in pain and that I don't understand. She doesn't fully listen or comprehend what I am saying or the doctors when they speak to her or try to explain information to her. She is says she is not actively wishing to die but her quality of life is so poor that she would be okay with passing on. She asked me a few months ago if I thought my dad would recognize her when she gets to Heaven. I said, I think so. I had 3 siblings all males. My oldest brother lives 70 miles from here but is battling health issues of his own. My younger brother lives about 45 miles away and works 7 days a week. He calls frequently but is unable to visit very often. His job also involves sporadic travel. I will be retired 2 years as of December 2017. I feel so far in over my head. My husband has health issues as well having had triple bypass 3 years ago. He also has uncontrolled blood sugars. Sorry this is long. I just needed to vent I guess. Don't know what to do when my mom is in so much pain.