Short answers, pulled from the story.
Jost Winteler was a Swiss professor of Greek and history at the Aargau Kantonsschule, as well as a linguist, philologist, ornithologist, journalist, and published poet. He is best known as the mentor and father figure to a teenage Albert Einstein, who boarded at his home in Aarau for a year starting in October 1895.
Jost Winteler met Albert Einstein in late October 1895, when the sixteen-year-old arrived at the train station in Aarau after failing the entrance exam to the Swiss Federal Polytechnical School in Zürich. Gustav Maier, a mutual friend of the Winteler and Einstein families, helped arrange for Einstein to board at Winteler's home for a year while he finished his secondary education.
Albert Einstein fell in love with Winteler's youngest daughter, Marie, a few months after moving into the Winteler household, and the two became a couple by Christmas of 1895. Einstein ended the relationship in May 1897, after he had already met his future wife, Mileva Marić.
On the 1st of November 1906, Winteler's son Julius, who had returned from working as a merchant ship's cook in America showing signs of severe mental illness, shot and killed his mother, Pauline, and his brother-in-law, Ernst Bandi, before taking his own life. Albert Einstein, then living in Bern, sent Winteler a letter of condolence three days later.
Jost Winteler died on the 23rd of February 1929, at the age of eighty-two, in Wattwil, in the canton of St. Gallen. He had retired from teaching in the spring of 1914 and had been living in Krummenau, also in the canton of St. Gallen.
Winteler's former home in Aarau bears a plaque noting that Albert Einstein lived there as a student in 1895 and 1896. In 2006, a building at the Alte Kantonsschule Aarau was renamed 'Albert-Einstein-Haus,' and Winteler was portrayed by the actor Nicholas Rowe in the National Geographic series Genius in 2017.