is there a reason why your father didn't call you to tell you and an uncle did?
Gotta lot of umbrage in you, my friend... it's not healthy.. I like Lurkette's idea of writing the letter and slipping it in the coffin and just letting those feelings go... but...
I'm kinda with your friend... enough.. you don't owe this woman anything.. however.. if this is your father's mother... would it be disrespectful of you to not show for him? Does that matter to you?
Awww heck... I need more coffee I can't make a decision...
Good luck