That's where he came into his life. His father-in-law.
Neither blood ties nor legal obligations obliged him to remain present. However, from the morning, he was busy preparing breakfast. In the evening, he lined the bed with care. He would go to school meetings, sit down to help with homework, and celebrate every little achievement with genuine pride.
Over time, the term "father-in-law" has naturally faded from his vocabulary. He had simply become a Dad. The one who had taught him to hold a handlebar, to take the wheel, to raise his head in the face of hardships. The one whose voice carried the furthest in the stands.