[He really shouldn't be surprised that their mother had help, or that Ai was that adamant to know him. Both women had that determined streak in them.]
Maybe, after I see mother and father, when the sun sets... we could go watch it together.
[Honestly he liked being able to wake up early enough to catch the sunset with her, but walking about in the day time like this was just as good too. They could rest later, just as they always did - with Ai holding onto him or him holding onto her. Smiling warmly, he squeezes her hand gently.]
As long as it's alright with onee-sama, of course.
[He still felt as if maybe he should hold himself back a little. There were things she didn't know, after all - namely him. She didn't seem to mind and seemed more than eager to rush forward until she remembered, but still he felt as if he should take care to watch her. The last thing he wanted to do was upset his sister by being too eager to spend as much time with her as humanly possible.]