this is really sad, but it is a very hard decision i dont like putting one down but if the aggression is getting worse. that may be the thing to do. as placing him in a new home i really dont think that would help, there could be a medical problem my gsd that i lost to cancer became aggressive went after me several times in one weekend so on that monday off to the vet we go. her cancer had spread to her brain. she was only 4 1/2 yrs old. my heart goes out to you i've been there and its not where i would want to be agin. take care and lots of hugs and prayers.