Shaykh Abdul-Muhsin Al-Abbaad was asked:
“The Hadith, ‘He who sees the letter of his brother without his permission sees Hell-fire”, does looking at the book of another student when studying enter into that’?
“This Hadith mentioned is weak. So it is allowed for a student to look at the book and there is no prohibition in that. What is forbidden is make it tight upon him or crowd him. As for a student looking or the owner of the book coming near and he is conscious of the other’s desire to share with him, then this is permissible”. End translation. [Sharh Sunan Abi Dawood no. 185]
Faisal Ibn Abdul Qaadir Ibn Hassan