There were gas lights and oil lamps. His family's Christmas tree had lit candles on it, just like everyone else's did. Sometimes the candles set the tree on fire. Sometimes they burned down people's houses. Science has made a lot of things a lot safer, and science has helped make many wonderful and amazing new things possible.
Computers are really new.
They are so new that a lot of adults don't have the slightest idea how they work or how to work them at all. When my son Steve here was in school there were no computers. He has to ask his little sisters about them. They know about them because they were everywhere when they went to school. If a grownup wants to know something about computers, they can ask a kid.