The First Few Nights
Hopefully, introducing your new boxer pup to your home will be a fairly simple process. You will have your crate ready for your new puppy, and he'll sleep in it at night. Keeping him in your bedroom with you during the night will help him feel more comfortable in his new surroundings. You might find that your puppy falls asleep with no protest and sleeps through most of the night. After all, he'll have his cushy new crate, toys, bed, and, if possible, something that smells like his littermates. That can be a toy that all the pups played with or a piece of bedding.
Don't expect the kids to take care of the boxer any more than you expect them to clean their rooms or take out the garbage. They will probably take care of the dog only when you stay after them to do it, and even then, they might not do a very thorough or careful job. This means that the dog's care will ultimately be your responsibility.
But what if it isn't so simple? If your pup has a real fit of home-sickness for his dam, his littermates, and his breeder, it's okay to pet him in his crate and give him a few reassuring words. Just make sure he isn't protesting because he really has to potty. When you are sure that he does not, calmly and firmly tell him goodnight, and prepare to wait it out. Some puppies just need to fuss a little, but it is usually over in about ten minutes or less. Remember that the less you coddle him over this, the more quickly he'll get over it. Coddling him at this point will only set him up to think that if he protests enough, you'll give in, and you don't want that.