I have no doubt Vito in his day would have been ruthles enough to kill Carlo, son in law or not. This is the guy who shot Fanucci in the mouth one time to many, just in case he wasn't dead.
This is definitely true. Not to mention, this is the same guy who gutted Don Tommasino to avenge the murder of his family. Don Vito is a tough fellow and also one who never goes back on his word.
