Visitor visa for sister(about to be divorced) and nephew

Hi ! I am currently on H1B and I would like my sister and her kid (6 years old) to the US on visitor’s visa. Sister is currently separated, have filed for divorce, the first hearing of which would happen during March. Considering the nature of sister’s husband, I am not sure if we would be willing to sign consent letter to send the kid to the US. Sister doesn’t earn much and doesn’t own any property. I would be sponsoring them for their expenses and stay.

Please advise how i can avail B1/B2 visa for them considering the situation. Would they face any issues during the interview considering the absence of the father?

Any help would be greatly appreciated !