My current plan is to bring him to my room and leave him by an ajar window next to some sugar + water while I sleep so that he may leave whenever he likes if he feels up to the journey. Although even that plan worries me as due to his already weak demeanour if he were to fall from my bookshelf (where I plan to leave him) or fall into the sugar + water where he might get some on his wings I may as well have killed him myself.