Apart from changing '4' into 'four', your sentences are grammatically correct.
I see no reason why you shouldn't use 'disappeared' as you are clearly not speaking literally. There was an 'icon' - a famous person - clearly visible in the public eye. Then the icon disappeared.
I really can't see anything wrong with it. We know that 'die' and 'disappear' aren't synonyms, but you're writing metaphorically.
'Both his parents have already died' is perfectly correct.
You could, if you wanted, say instead 'Both his parents are already dead', but it's no better than your original, perfectly good sentence.
Note, while it's certainly not wrong to say 'Both his parents', it's really not necessary, as two is the standard number of parents. 'Both his parents are dead.'