Our son is 22 and our daughter is 26. She bought a house in July. We know that moving into a new home always comes with unexpected costs, right after you've probably depleted most of your funds. So, for Christmas we gave her $4000. Our son we gave a few different gifts totaling somewhere around $800.
Our daughter had to work Christmas, but we did Christmas on the 26th and she stayed with us for the holidays from then until yesterday. Our son still lives with us, and today he told us both that he didn't want to say anything while his sister was here, but his feelings were hurt by the disparity in the value of the gifts.
We explained that the gifts we got him were tailored to his interests, but his sister has just passed a big life milestone where money is more important to her right now than sentiment. He said it's still hurtful because it feels like we are more proud of her than him.