[bELyVIS]

Why are you going to Japan if you expect everyone to change the way they do things to your liking? How can you truly experience another culture if they are not acting natural?
I hate fish, sushi, sashimi, etc. yet as a manager in my company there I was expected to go out to various functions (almost always at a sushi restaurant and making me pay 5000-10000 yen) and eat this and say "Oishi" (thank God for beer), and even not get angry when they (against my wishes) tricked me into eating Fugu (poisonous blow fish) when I didn't wish to risk my life for eating something I hate in the first place.
I think you should cancel. If things don't go your way there not only will you embarrass this family, but it will just add to the many reasons why certain Japanese dislike gaijin.