Holding forever - My father had Apple stocks in 1981

Because he was working at Apple, my father got Apple stocks for 4000 $ in 1981. He sold them about three years later when they doubled. Today, they would be worth about 5 million Dollars. He told me this story hundrets of times and it depresses him everytime he hears anything about Apple.

But would it really have been an realistic option to hold that stocks for more than 40? Who could have forseen that outcome?

I'm in the same situation right now with crypto. My crypto investment doubled and I could need that money right now. But if I sell now and have to tell my kids the same story in 40 years, I would have really not learnt the lesson.

What do you think?