Compartmentalization of Decay in This Tree.
If I could go back in time and warn these ppl I'd tell them the tree's likely time to encapsulate this wound was greater than the likely time for rot to set in and it should be sealed with SOMETHING.
Considering we put wax on the most delicate of grafts I doubt some xxx would have killed the fella.
In the next year or two its going to be time for the 100% tree killing chainsaw to come out and kill the tree.
IMO CODIT isn't useless. You just need to "calculate' the likely encapsulation time vs time for rot to set in. Location of the wond, growth rate of the tree, species, climate all that comes into play.
Good cut on a verticle surface of a walnut it will seal in 5 years, let it. In some rot trees, help them out.