Betta Fish: I think my 2 1/2yr old Katsumoto is crossing over soon and idk how to help

I’ve had my tangerine koi buddy for 2 1/2 yrs. We’ve been through a lot lol which sounds weird to say. He has been super healthy. Went through a color change, always super happy to see me come up to his tank with food, would swim into my hand while I’m cleaning his tank, etc. Never thought I’d love a fish so much 😅 but I do. He’s old, obviously, and lately he has been giving me some weird behavior. He will literally SIT at the bottom of the tank (pictured,) and will lay down in his floating betta log most of the day. He’s still eating, but just slow, and lethargic. The tank parameters are spot on, so I imagine it’s just old age. Is there anything I can do to help? Never thought I’d be sad about not having clove oil on hand 😔