Pacman frogs are pretty sedentary, so him not moving around much isn't concerning unless he's not responding to outside stimulus. Has he been seen by a vet at all to confirm he has neurological issues and it isn't something else? Do you know if he's been supplemented with calcium powder (with vitamin D3)? And what have you tried feeding him and in what way? Tong feeding is pretty fool proof unless he's outright refusing to eat.