Does his eyes seem to register movement in his enclosure? Heard from my veterinarian that especially albinos have bad eye vision since birth, but it could be that he's not that interested in the food cause it's small or it's to hot/cold in his terrarium. If you could a video of your frog eating would be good. Do you feed him with tweezers or do you put the food directly into hit enclosure for him to hunt himself?
Kind regards/ Leonard