I have 2 pitbulls, a senior dog around 15 and an 8 year old both males. My senior dog recently started to have health problems. His jaw just completely dropped down and he can no longer control it. I took him to the vet and they put him on antibiotics. There he was diagnosed with a heart murmur. While I understand I may have to put my senior dog down soon, My real question is My 8 year old has become depressed and kind of lethargic, he doesn't eat much and i'm worried.This started about 2 weeks ago, at first he was puking that kind of subsided. Now he just doesn't was to do anything and his personality has really changed. Could it be a health problem or do you think he is just depressed about the senior dog?