Why does my dog only bark at my brother when he comes home at night?

Question
Hi, I'm Tim and I really need this question answered.

Our family dog Katy, a 6 year old yellow lab, has been getting in to the strange habit of barking at my brother when he comes home at night. The thing is, she has never done this before and she does not try to attack him. Instead, she just runs up to him and starts licking him and wanting to play. I'm not sure what to do about this, since she never does it to me or to the other members of my family when we come home.

She has grown up with him around since she came to live with us, and she has spent a good amount of time with him, but not as much as the rest of us. I don't think it might be a lack of attention from him, because my dad only spends time with her when she comes into the house when it is late or cold outside. Plus, my dad is outside a lot when he comes home, but he doesn't pay attention to her all that much.

Answer
She could be happy to see him, or she could be feeling threatened or protective. Try keeping her on lead and correcting her at night when she does this. Also, do walk your dog twice per day, she needs to get tired. Please remember it's her job to alert and warn you to changes in your home. She might be just letting you know he's home :)
Diane