Thank you for caring...        It is so sad that this little one had such a hard time.  Thank you for caring enough to give him a home and a chance to be happy in his senior years.   
At 12 he is a senior.  He could be dealing with any number of health issues, generalized pain, hearing loss, weakened eyesight, etc.  If he was an only dog for a long period of time, that along with being a "grumpy old man" he may just need some time and space to adapt.  You mentioned about the gallbladder surgery, which was an emergency.  If he hasn't had a complete "well dog" checkup it would be a good starting place so that you know exactly where this senior is health wise.        |