3 Yr old

My 3 year old had been exposed to violence before his 1st birthday when his dad dragged me by my hair and tried to beat me up infront of him. I'm no longer with his dad, moved house etc so we would be safe. His dad went to jail last year and got out this year however since his dad's dad's released from jail I've noticed his sleeping has gotten worse, he never used to sleep all night but this was getting better to him waking up once and then sleeping till 8am now he'll wake up around 4 times, sometimes crying and be emotional in morning. My mum thinks this could be because of his dad and because babies and kids can sense things like this but I'm not sure if it could be or if it could be just because some kids do that. Help pls he also doesn't like people raising their voices at others in front him,people arguing etc and get very very emotional

We are not in contact nor see his dad he messaged me when he got out and I blanked and blocked him.