Okay so I'm not even sure how true this is, I feel like it isn't, as it doesn't seem legal?

So long story short, when my current partner took my son home today my ex partner (dad of child) told him that CPS told him I couldn't keep Jr because Cps supposedly told him that I cannot have my son due to a case we had about 5 years ago.. this conversation started because we mentioned if needed we could take him and get him back and forth to school because they were dealing with a death in the family.

The case was a false report by my vindictive mother, saying I was abusing my son, they made us take him to get x-rays, etc. The house at the time wasn't in the best condition either, we had a slumlord landlord, we eventually got those issues fixed during the time which cps was involved out of pocket.

Anyway, he told my partner this and I asked him about it. He told me that the caseworker told him that unless he stayed in the home that our son wouldn't be allowed to stay there. As far as I was aware the case was just closed, but now I'm being told that I cannot have custody of my son by myself and that they gave him supervision rights. He claimed they had another case come up and they brought that up during the case.

How is this possible? Would they really just leave me in the home if I was deemed a threat or neglectful? And if so why would I not have been informed by CPS or the court of this? I even had him registered in school by myself when the father and i broke up. I have two other children now as well, wouldnt they have taken them as well if i was deemed a threat?

I don't know if he is lying or if this is legitimately a thing that can happen, but I'm so confused and the anxiety is eating me alive right now..

Edit: Spoke with attorney, most likely a lie, but looking further into it. Thank you all for your advice.