I doubt he has fully accepted anything just yet.
There are 7 stages of grief, and he is more than likely in still in the first stage of denial (Just google, it's a very popular model). This stage can easily last for weeks. By denial, its not so much a matter of "my Dad didn't die", but an unwillingness to accept the fact on an emotional level. You basically put up a wall between your mind and your grief.
You should allow him grieve in his own way, by this I obviously don't mean to not be there for him, but accept that he may be in a fragile emotional state, and just support him going through whatever he needs to go through.
Either way, we''ll see you when you return, and I hope you feel better, I know you are probably in an emotional state of your own right now.