Merlin Olsen died on March 11, 2010 at the age of 69.
Merlin never died! He was Cursed by the EVIL Morganna into a tree and is stuck in it! But their is another prophecy... that in a few 1000 what ever years there will be another socerer 1 that can free...
he never did. he was cursed, but he escaped and lives to this day in woods and forests. trust me.
Niniane lured Merlin into a cave, where she used the magic she had learned from Merlin, sealing him in a rock.
Merlin lives outside of time, so death has no meaning to him. so your question has no answer because he hasn't died.