I met Norbert online through a common interest in Modified Newtonian Gravity (MOND) and the experimental determination of the Newtonian gravitational constant, big G. This was far from his main academic field, but he applied the same high standard of analysis as in his mainstream work.
He was working from home while suffering the side effects of recent chemotherapy, as was I due to a recent serious illness. He responded quickly to my emails, tactfully pointing out any errors and encouraging me to write up and communicate my more promising ideas. Without his encouragement I would not have had sufficient confidence to do so.
When part of my analysis suggested that one of his own hypotheses might not be supported by the experimental evidence, his reaction was that if it was the case, he would be disappointed but the most important thing was to search for the truth.
Even in his last days, he did not complain about his illness and few of those outside Imperial College knew. Even towards the end he was still exploring new experimental means of testing his ideas.