My two boys do not seem very close at all, they don't actually fight, but snuggle buddies they ain't! The last time Ming had to stay at the vets for a few days, Mac looked around for him and seemed confused. The good part is in a couple of hours he seemed to be enjoying his new title of "The Only Cat in the House". I hope Boo and Coco Puff adjust quickly. You don't need any more grief or worry right now.