[@JJ Doe] Simple things, complex things, mundane things ... anything to be honest. Its really a reason for Al to enjoy and justify liking Rui for who he/she is. Rui is epic, I think the asshole aspect hidden by the loveable angel thing is essential and interesting to explore when Relationships are being formed. Also, (s)he is really cute. So it compliment his modelesque appearance. 

On a serious note, I can see him going to Rui for advice, information, and just hanging out. Seeing that she's found a way to cope with being alone, It will be a learning experience for him.