No of course its not alright but she wasn't innocent either. It's not like he just turned up at her house, randomly said that about his daughter and then shoved his almost mother in law. Infact did it not happen at his home, where she came in uninvited? There's always two sides to a story. I think it's important to remember as well though that the way he was controlled so much in 1d to the point that he developed an eating disorder there's a lot of reasons why he would have reacted the way that he did especially if in his mind he was protecting his daughter from the same controlling behaviours.
I've just looked it up to remind myself, he didn't say he was guilty either he pleaded no contest so that things didn't drag out to protect Khai from having to see it all online when she was older. No contest means you're not accepting guilt but accepting a punishment.
It's probably all on here somewhere too