Welcome @Dameputtingonabraveface to the threads - appreciate your posts.
I can only imagine how difficult it was to support your child through that time 
@My2cents1975 I am usually very much on your wavelength but in this case am with others in feeling that Harry, as an adult, is responsible for his own behaviour. Many people have much more difficult childhoods than he, and manage to come to this conclusion well before the age of 40.
With regard to KC3, I'm not entirely sure what he should be doing in relation to Invictus.
It wasn't a Royal patronage, hence why it wasn't taken from Harry at the time when he stepped back from being a working royal (those were detailed at the time).
He can't interfere in the working of the charity - I can imagine the complaints to the Charity Commission about that (not least from Republic, who would love the opportunity).
The people with responsibility for Invictus are the trustees.