Something else that I thought could be a possibility, although I find it difficult as MH is deceased, I definately don't want this to seem as some kind of slur, merely speculation
What if all of this is the other way around.. What if MH treated DK as someone whom he called when it suited him?
We know what all of MH's friends, gf's, ff, etc thought of him, MH had to keep living up to expections of others, he had put himself in that position, all this adds to pressure, for release he had DK.. perhaps MH was not always as nice as he is portrayed, afterall he was human, there could have been a totally different side to him which noone knows or wishes to disclose
DK could have been one or the only person who saw & experienced this otherside. MH could have had DK come at his beck & call, anywhere, anytime, we sort of assume by now they did not just strike up a friendship that night
perhaps this is why DK was sort of hanging around in the places where MH frequented, not stalking, but hoping that MH might want to see/be with him.
DK might have regarded him as a true friend/lover, where this was not the case for MH.
This might explain how DK 'overpowered' MH, MH trusted him, but also did not regard him as anything other than a nerdy, non threatining kid, who served for convinience, whilst he had his back turned to DK ( for whatever reason) DK could have finally snapped & had enough of being treated unfairly & not in the way that he believed or was led to believe
Perhaps MH was cranky that night as he was used to DK doing what & when he was told, & DK was late or did not understand the instructions well, ei where & how to meet?
Hope this makes sense, as I am reluctant to tarnish MH's character, but this a crime & we don't know that DK was simply some nut case who went on some killing rampage - that somehow does not make sense either. DK, has been charged with murder, we know this,
we have yet to see if his laywer will also present that DK was some kind of victim in all of this too.
In regards to "watch the quiet ones" that seems to place quiet ppl in a category - perhaps some quiet ppl are sick of listening to loudmouth bs & prefer to occupy themselves with their own interests,
the perception that under a quiet person lies some demonic lunatic is perhaps abit outdated too