Gregor's Greatest Invention (2001)

Original title: Gregors größte Erfindung

Gregor, a young man, lives with and cares for his elderly grandmother. He's also a bit of an inventor. One day, when her wheelchair accidentally rolls down a hill and throws her into a pond, he gets an idea for an invention: A harness system that will let his grandmother walk again by supporting her weight. Meanwhile, her friends from the nursing home are trying to convince her to leave Gregor and live with them.