Was it right or wrong to be absent from an English lesson to sit with a friend and console him on the death of his father, and are there prophetic hadiths that support this?

Consoling a friend in their misfortune and alleviating their pain is a good deed for which reward is hoped, as evidenced by the noble Hadith (definition): "Whoever removes a worldly grief from a believer, Allah will remove from him one of the griefs of the Day of Resurrection," narrated by Muslim. Sitting for condolences is not legislated.