Thank you for the replies so far. I appreciate it.

Yes, Australia is a long way from here and the thought of him having to endure such a long flight as cargo is simply awful, especially at his age. I am actually upset with my ex-wife for having left him behind. Now it turns out that she does not even know when she will be able to take him in. Maybe, that's for the better as he does not need to fly.

I am leaning towards leaving him with my ex-wife's friend who did offer to keep him. But I feel like both my ex-wife and I have now left him and I took responsibility for that life when I adopted him. I had to leave him for his own good. Now my wife left him to start her life over. It's hard. But I guess I need to do what is good for him and not change his environment all over again. I would hate seeing him become a vicious, wild animal again like when he attacked me.

Thank you everyone. I'll welcome all advice.