US entry advice

Looking for advice. My sister in law lived in the US for 4 years, overstaying her visa. She worked, paid taxes and rent. She came back to UK a year ago due to family illness and now wants to return. She has booked a return flight via Dublin but has no intention of returning. She has convinced my husband to travel with her, assuming they get in he will return after the 2 weeks. So my question is will she get in? If she doesn’t is there implications for my husband? Could this stop him traveling to US in future? Thanks in advance, Lou Also as there are immigration checks at Dublin, is this where she would be denied entry or would she get to US and be denied?