Let's say, for the sake of argument, that they were just friends. Not BFFs, no godfather thing, just friends. Even with that relationship, he probably would have made the trip to Perth for the funeral. Many others who simply knew him or had worked with him made the trip. People who didn't even know him made public statements. Jake... nothing.
Then think of what has always been said by and about both of them... they were best friends. Jake is Matilda's godfather. And then ask yourself why, taking that into account, he has not said a word and did not even attend his best friend's funeral. It ain't because he was busy. Like I said, mere acquaintances have done both of these things. Why not him?
Because people handle these things in different ways. Maybe Jake just couldn't bear the idea. Maybe he's still in the denial and depression phases. Maybe he's still internalizing the whole thing and hiding from the world because
that's just how he deals. I think it's safe to say he's distraught because there's no other rational explanation for what would superficially appear as his complete disinterest in the whole thing. What's the likelihood--even if they were just plain old friends--that he just couldn't be bothered?
I remember when John Lennon was killed, some reporter asked Paul McCartney how he felt. "It's a drag, isn't it?" For years, I held that against him, thinking it was disrespectful, flippant and cold. God, this dude just doesn't care! What an a**hole!! Then one day it dawned on me what he was really saying to that reporter... "how do you THINK I feel, you friggin' moron? DUH. What a stupid question! Leave me alone, I'm mourning my lifelong friend. You're intruding on my private grief, and it's none of your business."
That's how I see it, anyway. Your mileage may vary.