It may even be that no vampire, no matter how old and experienced, can properly process emotional connections (at least, not those relating to positive emotions like love), on account of being dead. Given time, the vampire would eventually have constructed some sort of negative-emotional framework to make sense of Durkon's whole life, but it would have been a very different framework than Durkon constructed.

The whole thing reminds me of conditionally-convergent series. Those are infinite series that can sum up to anything at all, including positive or negative infinity, by just adding up all of the same terms in a different order. Durkon can sum the series of his life to converge on a positive total, while Not-Durkon can sum the same terms, in different order, to converge on a negative total.