[ He knows not even with Yu, originally by Yu's reactions and then a little later when Yu visited. Yosuke knows that they're both private people, but for Yu not to know about it...

Why was Souji keeping it so close to himself? ]

I know. Neither of you guys are. And it's not like it's a bad thing to keep stuff to yourself, but...we care about you, you know? Your friends. Your pain is our pain and all that so we can help each other out. Isn't that how it's supposed to work?

[ At least he thinks so. ]

Hey, I'll be a better friend in the future. That's a promise.