Revoking Sponsored Visitors Visa For Friend

I had sponsored visitors visa for a very close friend 2 years back, he got 10 yrs Multiple entry...but since then he is a lot changed now..we have had huge fights since then..he also cheated me of some money..since he sometimes takes care of my aunt (living alone in pune), i did not take action yet..but of late things have gone extremely downhill between us..I am not sure if it is right for me to let him enter my home at this point....I am also not sure if he will come to USA without my knowledge, how it would affect me.....he does not pick up my phone..and there is no chance of reconciliation with him..he even insulted my husband over phone.....
can I wash off my responsibility from him by informing USCIS that he is estranged now and I am not aware of when he comes etc..he is not a criminal and has a job back home..am i overreacting? I am also scared if I revoke he may harm my aunt...