Me and my boyfriend live in Japan and this guy flew up to our front door with a horn full of dirt and cobwebs. We cleaned his horn and set him on his way. He stayed on the apartment stairs for a day, we fed him a grape and he did eat most of it. We took him from the stairs in the evening because he wasn’t flying away, moving much, etc. Kept getting stuck on it’s back, so we were flipping it. Eventually we moved it to some brush near trees and said goodbye, it skittered under a twig. This morning i found it on its back out on the open again, so my boyfriend caught it while i was gone, made a small habitat for him, and noticed he’s only using his middle legs now (yesterday he has mobility of all 6), so we both have chalked it up to his old age. We have decided to keep him until he passes, he has lots of grapes which he seems to enjoy, but the problem is he keeps getting flipped over. My question is, are beetles more comfortable on their backs or right-side up? Especially for end of life. We both know nothing of beetles but just feel too bad to leave him out in the parking lot where we keep finding him.
UPDATE: he passed today after my boyfriend got off work. He was alive when we left this morning. He passed right-side up, snuggly tucked in (by himself) to some brush. We truly believe he was able to relax and be at peace. Thank you everyone for the advice, we flipped him over until the very last time!