Sextus isn't. He can and does empathize. He flat out says he doesn't have the compassion Septimus and Tavi do, and frankly he's not the type to understate that about himself. (I think his wife would have phrased it as "He could be a better person if he tried to be, an astonishingly good one, and I try to make him listen to that possibility--but it doesn't work as often as it should.") Gentleness turns up very rarely, kindness almost never I think. Fixing the problem is absolutely first--caring. The thing about happier feels is that if it's a side effect, sure, that's a useful thing!

Actually, there's an interesting amount of 'fair pay for service rendered' involved. A sense of justice. Magnus got to play in his Roman sandbox. Ehren was given a cause to devote himself to. Max was given the best and most loyal friend anyone could ask for. Amara was given Bernard (and vice versa). Isana... uh... okay yeah she doesn't get much as far as kindness goes. She's his son's widow and mother of his heir. She's useful. And there is sentiment, but not... kindness. Tavi gets to play in his Roman sandbox and fool around with Kitai (because Sextus does not realize it is permanent). In fact, he screwed up with Fidelias in not giving him that--well, not until he gave him (like Ehren) something to believe in. That is also partly sentiment, as they were good friends. Gaius dealings with Fidelias are in general extremely unkind.

He does indulge Tavi rather more (although ahahaha oh god all but setting him up with Kitai was probably as much "Eh, let the boy play a little if it pleases him, at least for a little while. Hopefully it'll get all those unwise decisions out of his system. Unlike his father. ....Hmmph. Well, I can hope"). It is absolutely sentiment there, a lot of complicated ones too. Thus my tendency to call him adorable sometimes, although sweet may have happened with his wife sometimes. She was a major exception to the rules. There is something major coming up that some would probably call sweet, and feels more sentiment to me--and, as a result, amazingly tragic.

And he doesn't connect well. And sometimes when he does, he betrays the trust with sentimental regret but without hesitation. Kills the sympathy and compassion I tend to feel are required for sweetness.

So he is a bitter, cynical, heartbroken, and horrifyingly isolated old man, incredibly worn down by a job he should not have had to hold so long, deeply ill, with about one thing to live for (Alera and Octavian are approximately the same thing, being the future), and one who knows he has far less of a conscience than he potentially should but does very little to change that, except when given some amount of prodding by family. Single most tragic figure of the series, in my opinion.