Thinking about the end of life makes me feel depressed

My grandmother is 87 years old. In the last five years, she has undergone bladder cancer surgery four times,
and she has been battling diabetes for 30 years; her blood sugar levels now spike to 300 after meals.
She also experienced symptoms of a cerebral infarction, received treatment, and was discharged from the hospital.
She takes about two handfuls of medication every day, but perhaps thanks to that,
she can still go to the pool for an hour or two of aqua aerobics and walk without a cane.
On top of that, her mental clarity is very sharp.
Maybe that's why she has become very pessimistic and depressed.
She says things like, "Why bother managing my health when I'm going to die soon?"
and "There is no hope."
When I hear her, I feel frustrated, but when I try to put myself in her shoes, I can understand.
Usually, people move forward with the hope that effort will soon lead to a reward,
but at her age, after surviving so many life-threatening crises, even hope itself must seem invisible..
She seems to be very afraid of death, and watching her makes it hard for me too.
Except for my grandmother, all the grandparents on both sides of my family passed away due to dementia or sudden myocardial infarction, often without even realizing it themselves.
I suppose when your mind is still clear, you end up having many thoughts and feeling fearful.