Emil's just trying to point out that not everything is dark and desparate, and things might get better later on. What else can he do? Tell Lalli everything sucks but that's life and Lalli just needs to toughen up? Pretend there's nothing wrong with Lalli and ignore his depressive manifestations? He can't "listen and learn" here, there's a language barrier. Given the situation, I don't see what else he could do.
No one here is saying that Emil needs to tell Lalli to toughen up, or that everything sucks and that's life, or to pretend that there's nothing wrong and ignore his depression - the latter is exactly what Tuuri is doing, and it's pretty well-established that that is
also the wrong way to handle it. The problem, here, is actually a problem that's common to
all of those reactions, including Emil's attempted pep talk: they're trying to make Lalli be
happy, when what he really needs right now is to know that it's okay to grieve. Offering quiet companionship, and a shoulder to cry on, was what Emil seemed to be doing earlier, and it seemed to be helping. It might not have been much, but it was something, and it did help.
So, yes, Emil's choices very much do not amount to "try to cheer Lalli up" or "pretend there's nothing wrong" - that's a false dichotomy. And language barrier or no language barrier, he seemed to completely miss what Lalli was saying
non-verbally: his body language, his frustrated tone... So yes, he very much could have learned something from Lalli's response, and didn't.
He doesn't need a "good reason" not to be friend with someone — that's a weird thing too; you can only step out of a friendship if the other person is being a jerk?? Well not for me, if I want to walk out, I walk out, and I don't have to give any reason for doing so.
I honestly don't see how this is relevant...