Answering my eleventh question!
We all grieve in different ways: Some are quick to fall apart, some rise up and face it head on, but others may not always show their true feelings on the surface. Sometimes they put their own feelings aside for the sake of trying to not make the situation worse. It may come off as strange that they aren't responding to a situation in the way one would think; but it makes sense, at least to them. Sometimes they have to be strong so they can help others; and maybe, they just don't want others to worry about them..
B-but of course this is just talking about "in general."