Close friends with Jimmy Savile. That speaks for itself.
Supported paedophile bishop Peter Ball after he was cautioned - both financially and in a series of letters to PB commiserating with him about the impact of his victims' attempts to seek justice. One of Charles's letters to him referred to one of his accusers as a 'ghastly man.....up to his dastardly tricks again'. (one of his victims committed suicide). Claimed afterwards that he had been 'misled'; apparently it did not occur to him to look into the truth of the matter.
That is quite apart from the dodgy charity work, cash in carrier bags, opaque financial dealings, profiteering though the Duchies on the back of charities and public institutions such as the NHS and the military, and being exposed as a slumlord. And that is just what we know about.