In a wider way, this applies to all of us as we age, and at any age as life naturally changes around us. For instance, an older (than me) friend was excited about a month-long driving trip she and her husband were planning when she had an inexplicable fall in the night and cracked her pelvis. She struggled with considerable pain, and not being able to drive, and finally realized they had to postpone the trip a few weeks. But as she worked to heal her husband fell and it was more serious - a seizure, perhaps. He has been hospitalized for weeks now getting all kinds of therapy and trying to adjust to medications. She told me that their life has a new design, and she doesn't know what it will be now.
That's very large, but things can change radically in other ways. How I suffered years ago! when I suddenly had a painful stress fracture and had to wear a soft cast and limp around, and stairs to my study were just too difficult. Now my feet are okay and I'm in a one-story house, and it's my chemistry. Depression comes and goes these days, and I have to cancel things. As for goals? On a slow day my goal is to endure the hours with minimal suffering. Ambitious goals, like submitting my poetry for publication - they come and go like the wind. On a bad day, I don't care, and there's nothing external pushing me. On a good day I want to do a dozen things. I don't have a steady thread of self giving me the discipline to work on major goals of that kind.
But good day or bad, I have fallen into having one goal every day: To be kind. It is not hard to be kind; it can be passive, not being unkind or doing harm. Not making the grocery store checker's life more difficult. Not snarling at a beloved person. Giving the cat fresh water. Calling someone on the phone to see how they are. Responding nicely to an e-mail or internet exchange. Sending a thank-you card. Like that.
The simple vow to be kind isn't hard, but it actually changes your stance toward the day. Instead of thinking about what you want, you are thinking about how your actions affect others. Like shining a light out in a dark room, instead of into your own eyes.