Toki no Maigo o Sagashite by Minaduki Yuu

Summary

Plot: Orphan since his parents died in an accident when he was 16, Akito lives with Kou’s family, his childhood friend. But following an accident, Akito becomes amnesiac, unable to recognize people close to him, places that were familiar to him, or any events of his past. Kou, who had been in love with him for a long time, takes care of Akito like a mother, trying to help him recover his memory. What if the amnesia was a new beginning for their relationship?