Can a Genjutsu awaken Mangekyou Sharingan?
Not possible, Sasuke didn't awaken his Mangekyou Sharingan after being battered by Itachi's Genjutsu. Itachi kept on replaying how he killed both Sasuke's parents. The Mangekyou can only be awaken when the user suffer from trauma after witnessing the death of someone close to them. With the user normally having to witness or experience this first hand not by Genjutsu. For further details please refer to Mangekyo Sharingan