How can I removed my sponsorship to my father, can I removed it now or until he becomes a US citizen?

I gave my father’s papers (served as sponsor) for a green card (he's had his green card for almost 4 years) and now that he has the green card little by little he started changing his attitude towards me and hiding information from me. He's also bashed me with other people and when confronted he's denied it. He now owes me over $10K and hasn't really paid me. There's always an excuse and I want to sue him for what he owes me. I know I'm obligated to support him but is this for the entire time until he becomes a US citizen? Does it matter that he has a job? He's also in the process of bringing his family; will a lawsuit affect his process of immigration for his family? I feel like he used me for papers just so he could bring his family.