In the spring of 2017, my husband Bill and I were getting ready to travel and do some charitable work. We’d finished raising our children and had been very active in our grandchildren’s lives, so we were looking forward to some time for ourselves.

Then, Bill was diagnosed with myelofibrosis. And all of our plans came to a grinding halt.

Fortunately, we knew what to do. One of our daughters was born with Down syndrome, and...