How sweet and thoughtful! I always get my son's dogs Christmas gifts. I call them my Grand-dogs. I'll bet that meant a lot to your brother and sister-in-law.
My dog, Princess, who is recently deceased, was very spoiled. We had her for 12 years. On her first Christmas, I (sadly) neglected to buy her a present thinking that my husband had taken care of it. She always had a smile on her face, but when all the gifts were open and she didn't get one, she clearly was moping. We realized the error of our ways, and fortunately, my daughter had purchased a toy for a friend's dog and had wrapped it. She brought it out and gave it to Princess, and you should have seen the excitement and happiness in her eyes as she opened her new toy. Animals have feelings too, don't they?