I’m so sorry to hear that – I went through the same thing with my partner. Refused to live with him because he was an alcoholic and drug addict. I lived alone with my son and we had a good life but social services came to visit – but don’t worry they found nothing to worry about because my son was thriving and healthy and had no issues. Try to stay calm and say your piece – they will hopefully see and understand that you are a good mother just trying to do your best in a difficult situation.
Make sure your eldest son is not allowed home under any circumstances.