While he attempts many times to touch Lala's breasts, he does not make it in time, and thus is stuck with the engagement.
Each character's profile is based more on the manga than the anime adaptation.
She stopped calling him "Onii-chan" and doesn't quite look up to him and respect him the way she had before.
Nevertheless, the two of them are still very close.
Rito always considers Mikan as his one and only precious little sister, and has shown that the thought of losing her would be too much for him to bear.
And Mikan is happy taking care of Rito at home, even though he very often does a great deal of chores and housework himself.