I agree that the root cause of the majority of the issues with H is the overly indulgent parenting that he received from both Charles and Diana. H has never had to connect his actions with any consequences.
Failed Eton entrance exams...still got in
Cheated in A level art...was not expelled from Sandhurst for submitting fraudulently obtained results.
Beat up RPOs...no consequence
Wore Nazi uniform...no consequence
Left base on lockdown for mandatory drug test...was not cashiered
IMHO, KC3 would have done H a world of good if, after hitting his RPOs for the first time, H was grounded, instructed to apologise in person and sentenced to clean out the royal stables for a six-month stretch, under supervision from Aunt Anne.