Well yeah I will explain..
Basically because Shoji is now in New Zealand and Frost's sister is having an operation right now on some tumors (Non cancerous), Frost doesn't want to be anywhere near the couple when they get back to Frost's house (Most likely). Plus he doesn't want them touching the xbox either incase they want to play something on the xbox 360 together.
On top of that I think he hates his sister AND shoji because they are together despite the fact that he warned shoji not to go near his sister.
So i guess that's a brief explanation and he probably hates me because I talk to her sometimes and stuff which I find is pretty stupid because I have done nothing wrong and simply talking to someone isn't really bad.
EDIT : Although he'll be on brink and stuff it sounds like he's forgot he has a girlfriend and such to go see o.o or his girlfriend is probably somewhere like normal.