Hi :o
I'm alrighty!
Yes, some choices you make will affect your relationship with Blake, but not all, some choices just influence what will happen during that one day or the day after, but only on small stuff. But there will be two ways to approach Blake through the choices you make, either lover or being your brother.
My plan for the future was to make a feature where you can see the characters info in-game and on Blake's info it should appear a heart (for lover) and a like (for brother) and since we are rewriting the story, we are adding the awareness of the choiches you make. The mechanism of character info will be added later in the future though.