Overthinking what was just a casual conversation will do you no good. Most people would anticipate feeling lonely after their partner dies. That doesn't mean that they are immediately going to rush out to look for a replacement. In any case, you wouldn't be around to witness what he might do, so why worry about it?
Two loving couples who live near me were good friends. One of the wives became ill, then died, and her husband was supported by the friends. Then the husband of the other couple also died, and she was helped and supported by the male friend. Eventually the two survivors married each other, which was a happy ending to a sad time, and was welcomed by both families.
Another female friend grieved very much when her DH died, saying that she would never find another like him, nor wanted to. 2 years later she married one of their friends from the local Social club.
No-one knows how they will feel, when bereaved. My DH died 6 years ago. I grieved for him, but also found a certain pleasure in living alone and pleasing myself, after many years of coping with his ill-health. I still wear my rings, and am perfectly happy to remain single. I doubt that my DH would have coped well on his own, though, and would possibly have re-married........if he could have found anyone willing to take him on!