My daughter had her head beat on the floor by my ex-husband. He is under a no contact order from cps,?

2 weeks ago my daughter was visiting at her dad's house, while there she threw a bit of a tantrum (by the way she is 5) and the end result was her dad sitting over top of her banging her head on the floor screaming at her. He is under a no contact order from cps, now his parents want to see my children...I'm confused as to whether or not i should let them go?