I was the owner of 3 cats. I recently had to put my 14 yr old cat to sleep. It was terrible and my other 2 cats were so lonely for him, so I purchased another cat.he is 3 yrs old and real timid. My cats will not accept him. He is real scared. I have done everything. I introduced them very slowly, but to no avail. They chase the new cat, hiss at him, and everything. He hides all day. I need help...