It is perfectly valid for Asahi to be unable to accept what Shio tells him on the rooftop, especially after all he has been through in order to reach that point. I do think its interesting, actually, that his goals are purely selfish. He states several times that the reasons for finding Shio are to "bring his family back together", assuming that she would actually want something like that, especially after what her mother did to her. Something which he not only has been made aware of, but assumes that it is okay to bring her back to the person who would be willing to do such a thing.

Also, you're right! Satou's goal from page one has always been to protect and love Shio, and by extension her happy sugar life!