Originally Posted by
AJA_
OP says the sister has already been denied the ESTA so that's not going to work.
IANAL but I would strongly advise people not to lie on ESTA applications. The consequences if US Border people do find out you've lied is not worth thinking about.
Others have advised what options are open to her and they are limited.
Yes, lying is a real no no and will have serious repercussions. The best advice as said before is to get the earliest slot possible and hope you get a sympathetic ear in your interview. I know a former US citizen who applied for an ESTA, was turned down online and had to be interviewed. They were very interested as to why she had renounced her citizenship and she did not get an easy time in the interview. Fingers crossed your Sister in Law has an easier time in hers.