I suggest a new stash of toys if they are the type to take new toys eagerly. Also make sure your brother has the name and number of your avian vet, and that the vet knows you are going out of town and your brother has care of the birds, just in case. I would leave a list of their likes and dislikes on the fridge (loves apples but hates having his head scratched, like to step up but don't try it if he is on top of his cage, that kind of thing) so that your brother can have access to some of your "insider knowledge." In general, you can only do so much, but I find that my birds tend to be more cuddly when I return than before I left. Also, I would make sure your brother handles the birds with you around quite a few times before he does it with you gone - there is quite the difference between birds of prey and conures! If you are not comfortable with how he handles the birds, have him leave them in their cages. It is not ideal, but birds can get in a lot more trouble outside their cages than inside, and you will not be home to save them from themselves. I have only ever had one friend (besides my family members) who I allowed to take my birds out while I was away (She is a parrot owner herself), and everyone else I leave VERY STRICT instructions that they are not to let the bird out no matter how cute he is! I do this because I once had a bird injured because the pet sitter thought she was cute, got her out of the cage, and almost let her crawl into a hole in the wall - the injury was minor, but was caused by his last-ditch effort to stop her from climbing into the wall. All that to say, be sure they will be safe out of their cages, or make sure they stay in them. It won't make them happy, but most things that keep us safe are irritating. Best of luck!