My German shepherd seems withdrawn, it concerns me, as my daughter is unable to have him with her, too many steps at her place. So he is here with Grandma and Grandpa. Recently we had to put his sister to sleep, elderly with health issues. I am not sure if he feels sad each time my daughter comes and then leaves. He is older too with sore hips. I don't like to see him feeling bad without knowing why? Any insight would be appreciated, thank you.