"There's a thing that they teach in Buddhism when you see a dead animal in the street — a pigeon, a little bird or a rabbit. You say to yourself, 'That is the way of all life and that is the way it will be for me.' And it makes you lose your fear of death."
Billy insisted he has no time for "nonsense" about reincarnation or realms of angels.
He added in an interview with The Times newspaper: "I think you go to the same place you were before you were born. Nowhere.
"You die. It's over. You should have done it when you were alive. Get on with it."
To try and ease his Parkinson's symptoms, Billy takes seven different prescription pills and practises meditation every day.
He said: "They keep me steady. I seem to be on the medium to mild side. Take a walk on the mild side."
He has tried alternative therapies, including cannabis, but felt they weren't right for him.
He said: "I get bombed out of my head. And I don't like it. My daughter bought me cigarettes with CBD. It helped a little, but not enough to write home about."
The 'Mrs. Brown' actor gave up stand-up comedy because of his health and he's "glad" he made the decision.
He said: "So far I don't miss anything. I'm glad I made the decision. I don't want to be on stage with my symptoms showing. I can't."
"There are guys who do really well — there's an American boy who says, 'Shaking is the new cool.' He's got it on a T-shirt. And bless him, but I don't want to do it. I had fun on my last tour talking about Parkinson's, but that's enough. I don't want to be a disabled comedian; I don't want to be a comedian you feel sorry for."