Hi Eunice,
Orange is not coping well with the new environment. There's nothing in the new hse which he is familiar of. There are none of his markings too.
Give Orange some time to adapt to the new environment. And, if Orange is intimidated, ask the owner not to go to Orange but rather let him go to her instead. Orange prob feels insecure, and chose not to eat or sleep.
A word of encouragement from the owner should help. No doubt she shld spend quality time with Orange, she must also give him space.
Audi,
Right after Nanook was neutered, he was groggy and quiet, refusing to eat too. A while later he was climbing up the window grilles. He began eating and drinking the day after.
Perhaps you could check with ure vet. Tell him/her ure observations and ure concerns. If possible, bring them down for another round of check-up?