Extended author's note:
Sakumo is a very interesting character to write. :3 And I love him, he's awesome. He gives me the impression of being the badass shinobi version of a gentleman, y'know, and he seems sort of traditional in that sense. He's mostly polite, formal and composed, (which brings to mind Kishi's original plan for Kakashi, but nah. Sakumo's pretty different.) with a very professional attitude. He manages to be chivalrous and respectable... in the shinobi way. Crafty guy. :3 And still badass. *_*
His son has always been a very professional shinobi, but post-Obito he prefers to appear like a lazy perv who can't be bothered to be punctual, and can be quite a "casual asshole" sometimes, too. XD But both Hatake men are the most badass and professional shinobi you'd ever find, and both of them know the value of human life. \o/
As we all know, Sakumo is willing to choose to save his teammates' lives even if it means failing the mission. There's a lot of bittersweetness to him, too. Especially with his wife's death, and the war, and that genius growing-up-too-fast-in-wartime son of his.
Towards Chiyo he is... quietly apologetic (for the loss, not the killing) but unyielding, as I mentioned in the fic, because he can sympathise with the situation, and he's the one who killed them. But he also refuses give any more than that quiet but unyielding apology, because... well. It's war, shit happens, and he was just doing his job. (he's just too polite, and opts for "It happens." instead... I admire his composure and self-restraint.) He has his own loyalty to and duty to protect his own village, after all.
The fact that Chiyo's poison gas killed his wife doesn't exactly make things easier, too. He's sort of – "Yeah well that sucks, but I'm not going to die just because you want me to. Tough." ...'cept that's the way a pissed Naruto would probably put it. XD
Chiyo, just like her first appearance in the canon plotline, has her somewhat justifiable reasons for acting this way, but I won't be surprised if you do feel a little pissed at her. It can't be helped, y'know, humans can't be perfectly objective. I think Kishi meant for her to piss people off at first, but as the Shippuuden plot progressed we get to see things from her perspective too, and the whole Sasori battle thing made her officially awesome. XD Her decision to revive Gaara was also a redeeming point, I guess, because it shows she's willing to change and fix something she was partly responsible for (she did help seal the demon in him, after all) ...even though she could easily have chosen to not do anything. She was on orders, just doing her job, when she made Gaara a jinchuuriki.
Sakumo would be freaking out silently and on the inside about how Chiyo FREAKING TRIED TO KILL HIM WITH TEN EXTREMELY DANGEROUS PUPPETS XDDDDDDDDD but he has too much self-control to show it. I ADMIRE HIS COMPOSURE.