i work as a dog sitter and often take dogs for long periods of time ... i usually ask the owners when dropping off the dog to provide some things from home like their bowls, favourite toys, even a crate ... and i have one client who leaves a stinky sweatshirt of his in a crate but i do think the dog likes that ... and to be honest, the most neurotically dependent dogs are into a new routine within a week, most dogs it is only a day or two ... and don't think by me saying that, that the dogs do not miss their owners, because even though the dogs are quite happy to hang out with me, when the owners arrive back i could be invisible ... you have nothing to worry about ... it sounds like you have a good place for the dog to stay and you should think of it as you are both going on vacations ... and hopefully you will both have great vacations ... there is nothing you can do to make him feel better, if it was my dog i would verbally tell the dog that i was going on vacation and would be back, to not worry :O)