Putin Claims Support for Kamala Harris
https://www.newsweek.com/putin-claims-russia-supports-kamala-harris-joe-biden-us-presidential-election-russia-1949132
Only USC's are eligible for US Passports.
Are they related to your Nephew?
Obviously as others have mentioned details matter, assuming they have used a legitimate adoption agency they will be very familiar with the process.
https://www.soundimmigration.com/i-864-enforcement/
If this does not scare you, well it should.
USCIS are not going to be interested unless you have SOLID evidence of immigration fraud, not marital issues.
I agree with the others divorce asap.