So really the only good guy *spoiler*

Yep. Aside from Alex who for most of the movie had nothing but good intentions until he saw what happened to his brother & mother (he of course thought Grace was responsible for Daniel’s death) and eventually saw the light, Daniel was the only member of the Le Domas household who didn’t want to hurt - let alone kill - Grace. He helped her from beginning to end and ultimately got killed trying to save her. Also like he himself said -- someone had to put an end to the family’s madness and he pretty much succeeded in doing so.

So not including Grace herself, in the end Daniel proved to be the only redeeming/good person in that house.