crazy cat

Question
Hi my sis has a cat that was found in a tire as a kitten he is five now and has become aggressive to the point that  she is scared of him and he it attacking the other cat so bad that she cant leave her house.  he was always temperamental but she recently moved twice in 6 mo and the stress has been too much for him. i told her to put him to sleep it is the only humane thing. Of course her emotional attachment she is finding that too difficult. Could he be "crazy"  I know he is dangerous no rabies signs  just evil.  he likes to be under the covers of her bed and if you sit on the bed he growls till you get off.  he wakes her up in the middle of the night at her face on her pillow growling ....   could there be anything that we are missing?  anything (meds or techniques_ that may help her live a somewhat normal life?

Answer
Tough to know for sure... if he was a wild cat, then he may never get used to people or other pets. Especially after five yrs.  I agree the moving is very stressful for the cat. You know, cats can get anxiety/depression like people.  Talk to the vet about some of those options. He may suggest over the counter products first if he thinks it is worth a try first.  He will want to rule out health problems.  I can tell you the over the counter things that are out there, but why waste your money if your vet can get right to the problem?