Make burrowing shallower and softer
An elderly Pacman frog spends his life half-buried, and digging is the hardest physical work he does, so ease it: keep his substrate deep enough for him to settle his eyes level with the surface, but not so deep that an aging frog exhausts himself excavating a new pit each time he shifts. Keep that substrate evenly moist — dry, packed soil resists digging and dries his skin — and free of sharp bark chunks his belly must drag over. When he chooses a burrow spot, leave it alone; an old Pacman frog who must repeatedly re-dig after disturbance wastes energy he no longer has in reserve.
Set water at surface level, right beside him
An elderly Pacman frog will not travel far to soak, so place a very shallow dish sunk level with the substrate a short shuffle from his burrow, with water no deeper than his chin when he sits in it. He should be able to slide in and, just as importantly, climb out without a rim defeating his short legs. Change the water diligently; a sedentary senior frog sits in his own environment all day, and stale water against aging skin invites trouble. If he stops using the dish entirely, mist his corner more and note the date — hydration habits shifting is a senior signpost.
Feed him by tongs, right at his mouth
An elderly Pacman frog hunts by ambush and his strike slows with age, so present food on soft tongs directly in front of his mouth and let him take it without chasing anything across the enclosure. Offer slightly smaller items a little more often, and count what he actually eats; a frog who lunges and misses repeatedly, or who watches prey pass without interest, is telling you something has changed. Feed in his burrow spot rather than digging him up for a feeding session — hauling a senior Pacman frog out of his pit for meals trades his rest for your convenience. Vary his insects and dust them as your vet advises, since an old frog's reserves are thin.
Keep his corner warm, dim, and boring
An elderly Pacman frog wants predictability: a steady warm side, subdued light, and long stretches where nothing in his world moves except his food. Move his enclosure away from household vibration and curious pets if it is not already, and resist rearranging decor — he has mapped his small territory by memory and smell. Handle him essentially never; his skin absorbs oils and anything carried on hands, and a senior frog's skin barrier is the weakest it has ever been. Clean his enclosure with spot removals around him rather than full disruptive dig-outs whenever hygiene allows.
Read the small changes, and know their threshold
An elderly Pacman frog who stops burrowing and sits exposed on the surface, whose skin looks dry, reddened, or patchy, or who refuses food across several offerings is past normal senior slowing and needs an amphibian vet. Bloating, a hard swollen feel, or difficulty righting himself if tipped are urgent signs. Because this species barely moves even when healthy, your dated notes on appetite, posture, and burrow depth are the evidence that separates his normal stillness from decline. Keeping those notes together in his KinsLe Pet Passport gives a vet his real baseline the moment he needs one.