About why the cited sources gave 67 as his age at death, there is more than one possibility.
- Maybe they just didn't know (and didn't care to search for) the day of his birth.
- They rounded up his age to the nearest integer.
- They used the Chinese way to calculate the age ๐
Actual Age vs. Nearest Age
In support of point 2, it's common practice for both Italian and foreign insurance companies to distinguish between "Actual Age" and "Nearest Age". In order to calculate your life insurance premium, for example, a lot of insurance companies will round up your age to the nearest birthday.
Answers to "How old are you?"
There is no rule about this, but a lot of people, me included, don't wait until birthday to say that they are one year older. This is true expecially if they are young. Infact, it's not rare to add the word "compiuti" (turned) or "non ancora compiuti" (not yet turned) to one's age. And due to this habit, if you just say "ho 20 anni" (I'm 20) you may also hear somebody asking you "compiuti?" (already turned?)
In the case of Francesco Di Giacomo, his closest birthday was the 67แตสฐ (183 days from 22 August 2013, 182 days to 22 August 2014).
Just fo fun
The funniest way I encountered to answer the question "How old are you?" is the one of a dear friend who, when he was 60, used to answer this way:
40 ... to 100!
And when the next year he turned 61:
39 ... to 100!
He says that each passing year he feels younger.๐