Chainsmoker Henrik died aged 52 from lung cancer - the same condition that Richard's late wife Joan died from in 2021 - when his son was 24.
Richard said he never felt safe at home and was "piggy in the middle" for the last nine months of his parents' relationship as they were no longer speaking.
After her death, Richard wrote on social media: "We had an incredibly complicated relationship, and she was somebody that was, for me anyway, emotionally withdrawn and withheld approbation or approval of anything.
RICHARD E Grant has revealed his alcoholic father fired a bullet at his head in a harrowing childhood moment.
Prior to his parents' separation, Richard admitted he lived with guilt after seeing his mum have sex with Henrik's best friend in a car.
