I have a family Market Garden anecdote. One of my great uncles was a paratrooper and was dropped at Arnhem (survived and captured). His brother was attached to SHAEF; his job was to give Enigma decrypts to Eisenhower; because Enigma was UK eyes only there needed to be a Royal Signals unit attached to SHAEF to handle Enigma. Because of Enigma decrypts* he was aware that his brother was about to be dropped into an area with a large number of German units who were aware that something like Market Garden might be attempted. Montgomery disbelieved 'the signals intelligence' (presumably not being aware of the true nature of enigma), Eisenhower demurred from interfering with a British operation. So one brother knew the other was going in to what was likely a disaster.**
What was particularly poignant was the brother who was a paratrooper had been dropped at operation Torch, captured and ended up in a prison camp in Italy escaped and had just rejoined his regiment, and was then dropped and captured again. The other brother had been exempt from conscription because of civilian occupation, but joined up because after Torch his brother was posted MIA believed killed.
*He said his unit was perhaps the most knowledgeable about the war as they handled all the Enigma (and similar) UK intelligence going to Eisenhower. They had to personally hand the decrypts to Eisenhower's office, and frequently had to refuse Senior American officers who offered to be intermediates.
**There was also a policy that any Enigma intelligence utilised had to be sourced to a non-Enigma origin. So if Enigma revealed a German unit to be operating somewhere, then there had to be a non-enigma source before it could be utilised, so a reconnaissance flight might be sent out, or signals intelligence might focus on a particular area. So Enigma intelligence on German units in Arnhem would have to have been attributable to Sig Int and photoreconnaissance to be actioned; only the classification that this was Enigma level intelligence revealed its true source.