How to tell my abusive husbands family what he is like ..?

My husband who is abusive and messed up has told his parents I'm not giving birth in america but I'm my home country the UK. He didn't fully explain and it made me look bad, now they've kicked off telling him to fight for full custody and all of this.. Completely unaware that he abused me and that is why I left .

I talked to his parents and I talk to his sister we were kinda close but I have no evidence they kicked off apart from to just take his word for it. He could be making it up he said to me that his mum was kicking off and reacted badly but he didn't tell me exactly what was being said.

He has got his family involved but I really feel like speaking to them I just don't know what to say :/

Please help