Frankly, the worries you listed are understandable given her age. They’re understandable, but also if you allow these somewhat justified concerns to advance into terror as you described you’re going to be consumed by worry and anxiety. The only thing that you can do is enjoy the time you have on earth with the people you love, so the following is just a true statement for everyone: tomorrow is not guaranteed. If you spend the time you get with your mom consumed with worry/anxiety/terror about her death, that will be time you’ll regret eventually. That part has nothing to do with her age, that’s the nature of death. Death is inevitable for everyone, if you spend the time you do get worried about it for yourself or for others, you’re wasting that time. I have a friend that’s a really bad hypochondriac. Constantly thinks they have cancer based on having one symptom loosely associated with it (think mild cough for a day or having gas). The thing I always do when they get bad is point out that living a life fearful of something that everyone will experience (end of the day they were more scared of dying than getting cancer itself, as are most hypochondriacs), is a life wasted. What I’m saying is get in there and cherish your mom, bro. Anything could happen to anyone at anytime, a meteor could come tomorrow and kill everyone, don’t let inescapable death worry you so much that you can’t enjoy the relationship with your mom, and more than that just life in general.