Please help is this considered abuse?

A.💕
My ex husband is accusing my current husband of abusing my children because supposedly my children are scared of him and never want to see him again... They said that he grabs their arms and squeezes their head and pulls their hair... If they don't listen or he needs to redirect them he will grab their upper arm and move them or whatever and the same with the "squeezing of the head" he uses one hand over the top of their head which turns their head and once my son has cried because it pulled his hair... I've corrected my husband telling him he's obviously being too rough... But is this abuse? Or are my kids just being over dramatic? He's never spanked them and never so rough that it's left marks or bruises of any sort... My ex is bringing them to a psychologist today and has already filed paperwork with the courts and I'm freaking out... I would never put my kids in harms way and if it's true that this is abuse my husband has already said that he is leaving but either way I'm hurt because I love my husband and I love my kids... When they're here they love him and can't wait to see him they beg to go places with him... They never act scared... I would've never thought this was abuse!!! Please help me