Hang him.
Now.
No. it would be better to douse him in gasoline and set him on fire. Let him suffer toe same fate as his victim.
No, don’t hang him.
Let the kids or grandkids of that vet mete out a punishment that fits the crime exactly - light HIM on fire.
First toss him in a barrel of battery acid. Then hang him. Then burn the remains and scatter the ashes in a pig pen. How could you set a living human on fire, an elderly man who only knew to do good? Contrast and compare him to this worthless waste of space and oxygen, who probably can’t name his father.