You are right, the price for relying of very old memories. His service was from England (I presume in US aircraft). See detailed link below.
https://www.nps.gov/articles/000/joseph-patrick-kennedy-jr-a-dream-unfulfilled.htm
After reading about his deadly mission here, and looking at what happened subsequently to the Kennedy men who were politically active, I find myself wondering if the premature explosion might have been planned. I have heard that their father who was serving diplomatically in England was not well liked by some powerful people.
Old Joe Kennedy could well be called "pro-Nazi" in the sense that given a choice between Nazism and Communism, Kennedy would choose Nazism as the lesser evil.
Kennedy believed Germany would defeat Britain and clashed with FDR over FDR's anti-Nazi policies.
So Old Joe was replaced as ambassador in November 1940 and later blamed FDR for Kennedy's son's death over the English Channel.
Old Joe's feelings toward Germany give special poignancy to Pres. Kennedy's June 1963 speech in West Berlin, whose most famous line was Kennedy saying, "Ich bin ein Berliner".
"Two thousand years ago, the proudest boast was civis romanus sum ["I am a Roman citizen"].
Today, in the world of freedom, the proudest boast is 'Ich bin ein Berliner!'...
All free men, wherever they may live, are citizens of Berlin, and therefore, as a free man, I take pride in the words 'Ich bin ein Berliner!'"