From the LN translated into English that I've been reading on Wattpad, sad news guys, it doesn't seem like he'll be remembering any time soon. (Still crying about their situation 5chapters later which will probably be like 20+ chps in the comics.) I feel like Lucas is the only solution. I wish I had better news to give... ah but to keep the heart from crying out again- Claude does try to remember Athy. Tbh, I want to ask for a time rewind but that's the third-best solution atm. Second-best is if he remembered/the spell was broken. Still, at least Claude tries to get close to her even without his memories.
p.s. more heartbreaking scenes to come.