Can I refuse to play the piano for my family?
Why do you not want to play the piano?
I hate practicing, the piano is annoying
While it is nice to play for others, it is okay if you don't want to play for them. You shouldn't force yourself to play an instrument that you don't care about otherwise you will become more resentful.
I'm going to force myself to play
There's no need to force yourself, just tell your family that you don't want to practice the piano right now.