I think the grandparent comment’s author forgot to insert a “British” in front of monarch.
Edit:
> [Simeon II] is, along with the current Dalai Lama, one of only two living people who were heads of state from the time of World War II. https://en.wikipedia.org/wiki/Simeon_Saxe-Coburg-Gotha
However, Elizabeth II did not become Queen until well after WW2.
(Removed erroneous statement about the Swedish king being old enough to remember WW2; he was born in 1946.)
"she was the last British monarch to have any memory of WWII" is pretty weird too, though, since her father George VI was the only other monarch alive during WW2. I guess unless you also count her uncle Edward VIII who was alive throughout WW2 and had previously been a British monarch. If that counts then sure, she was the last of three British monarchs to remember WW2.
The British monarch is one of the least powerful heads of state on earth. The president of Barbados has more discretionary power.