I am fostering an older, male English Bulldog who is approximately 7 years old. He is as sweet as can be; but, has sever dog aggression towards my 2 year old male English Bulldog. The older one will get this look in his eye and begin to shake, and then the attack. The younger male won't really fight back. I haven been bitten several times breaking up fights. We have tried, Prozac, Xanax, a combination of the the two and we are currently using a shock collar (which I absolutely hate; but there is no alternative). Yes, I should try and find a home for the older one. Not many people want to adopt an elderly dog who can be aggressive towards others. Any advice on how I can get these two males to get along?