Mortimer,
Don't feel bad about posting. It is good to post.

As far as being there for your grandmother...I lost my father in November and the things I remember most are the people who were just there. They didn't do anything "special" they were just there.
Maybe you gould offer to help your grandmother with errands or cooking or some other tasks that seem simple but are hard when you are grieving or worrying.

Mostly just let her know you care and also take care of you. It is hard for you too.

Take care and we will be thinking of you. Let us know how you are doing.