Arthur lived in a cat room with a number of other cats in the shelter, so he wasn't really attached to his brother. He actually was friends with an adult cat. The good news is that the brother was immediately fostered and adopted, and soon after that Arthur's big friend was adopted too. And now Arthur made good friends with our 4 other cats!
No worries, his brother was supposed to be fostered right away and was adopted by the fosterer soon after. And now Arthur made friends with our other cats.