US citizenship seeking to discontine being a sponsor for a Green Card holder relative

[edavt04]

Hey there!

I filed and obtained a green card for my Dad ( I am a US citizen), however recently our relationship deteriorated after a big argument we had. I do not see us repairing our relationship in the future.
I sponsored his Green Card, but I was wondering how I can stop being responsible for him from now on.
Thanks!
edavt04