My impression was somewhat different; That Itsuki had tried continuously off and on but couldn't figure out how to hold a conversation and had in the end given up. This means that he is willing but doesn't know how. Takuma, one would assume, as a long time friend must have witnessed this process, but done little. He should know what Itsuki enjoys doing, so how hard could it have been to invite Itsuki and one other friend over to do something together? And once Itsuki was comfortable with this new friend, add another? Rather than Itsuki always being confronted by a group social event which can be daunting for anyone.
But heck, that may be expecting more reality than I should.
Maybe he must have done things to help, u don't know just as we don't really know if Itsuki put in any effort. Maybe he did invite but Itsuki refused , in the chap 1 or 2, he was the one that invited iTSUKI along and was surprised that he agreed. I don't think you can force a person to socialize if they don't want ( me and my friends are an example of this). The decision to socialize with others should come from the person himself, it should not be the responsibility of his friend.
While it isn't the responsibility of the friend, it is a question of wanting to help a friend. Otherwise why did Takuma invite him? In fact why did he invite Itsuki, as he clearly didn't expect him to accept, and it certainly isn't the sort of social gathering where Itsuki would feel comfortable? The nice reason would be to be nice and a good friend, the less nice would be because he never expected Itsuki to accept, and every time Itsuki refuses he would only underscore the image of himself as socially hopeless and dependant on Takuma.
All I'm saying is that by what we've read so far, Takuma could be great or not so great. There just are some odd remarks and stuff that made me wonder. But nothing conclusive. But you can make a good argument either way. So I look forward to seeing how it turns out. Personally I hope Takuma is worthy of his trusted friend status.
I still have mixed feelings. I think that he honestly intends to be a good friend but I'm not sure if what Takuma does is always for the best. I mean, given this particular situation, where he knew and understood the feelings of both involved, why didn't he at least try to talk about it to Itsuki? Instead he let Itsuki go on believing the worst of Yuno. Takuma decided on very superficial evidence that Itsuki was ok and seemed to rationalize not having to tell him, despite that there was actually some evidence that Itsuki was less than happy.

Wow- that update came fast. A good thing, as I'm on pins and needles for the next. So thanx to the team! :)
Do wonder a bit about Takuma, is he being more than just a protective friend? That line about Itsuki going back to being the "way he was before" would mean a totally shy recluse who had noone but Takuma. Also can't help but wonder about a friend who for years hasn't found a way to include a shy but WILLING (i.e. not antisocial) person slowly but surely in his circle.
So not saying anything definite about Takuma, he might be the best friend a man ever had, but if he turns out less angelic I wouldn't be surprised.