At the mention of his mother passing away, Shinji glanced at Dorian curiously, particularly with regards to the comment after that. He briefly wondered what Dorian's life had been like, but was of the opinion it was rude to pry.
A small smile appeared on his lips as Dorian expressed his wish to remember friends forever. It was a nice thought, but it seemed a little naive. "That'd be nice, huh". Some friendships lasted, others didn't; the slightest thing could turn even the closest of friends against each other. As for the rules making them hate each other, Shinji wasn't entirely sure whether it was that, or the fact that it instilled something akin to an 'each man for himself' feeling, prompting each person to (more obviously) look out for themselves and their own. It seemed to Shinji that, however unfortunate it was, those kinds of rules simply exposed people's true natures.
"They are unfortunate. You seem like... A really nice guy". In some ways, he reminded him of Shuuya. Shuuya had always seemed the sort who wouldn't dislike or hate someone unless he had a very good reason for it. Dorian seemed less spacey than Shuuya, though, and different in other areas - more childlike.
As Dorian commented on balloons, Shinji turned his gaze to a few, regarding them for a few moments. He couldn't say he'd ever really had an opinion either way; they were nice enough for parties - such as this one, he supposed - but other than that... He didn't consider them anything special. They always made him think of birthday parties from when he was younger. Yutaka, when they were little kids, had always been fond of balloons. "They're kinda nostalgic", he commented.