I have a 7 y/o lab newfy, Cosmo, that we adopted about 4 years ago. He was chained outside and never around other people or animals for most if not all of his life. When we adopted him, we already had an adult chihuahua in the house. Cosmo never interacted with the chi but does chase our cats if they run. He has become increasingly anxious the past year and now seems almost like he is having hallucinations. He does not get along with other dogs and will try to attack them. My question is do you think he would be able to adjust to another small dog coming into the house? Again he didn't have any problems with our chihuahua but maybe that was because she was already living here when Cosmo joined the family??