Impossible to understand. I think we have said it here before, but I guess that's why the only vague emotions he expressed were about such literal things - that "those kids" wouldn't be around for him to give them dinner or turn on their rainmaker or do domestic tasks for them. A few cliche comments about "Their smiles light up my life." That the house needed them. But totally devoid of emotion, love, grief, distress, regret, or remorse for these darling little girls. I would actually feel sorry for him that he is somehow missing this chip, except - he knows right from wrong. He knows murder is morally wrong and a crime. He's not a victim. He was of sound mind. And he did it anyway.
Any regrets or remorse at this point will just be for his new quality of life. His pesky family aside, he had a pretty nice life of a job that let him be outdoors, grilling his chicken, going for runs, watching football, going to concerts, driving his truck, snazzy new fitted t-shirts. He had it pretty good. I would imagine he is feeling very sorry for himself and perhaps regretting the predicament he now finds himself in.