<human>: Give me the gist of the text in a nutshell

I need your brutal opinion and advice, reddit. Long story: The ex and I broke up 8 years ago, I held primary custody (out of court) of our 2 children for 7 years. I had a restraining order at one point because he threatened me and there is a substantiated case where dad hit my oldest with a belt and left bruises (4 years ago). Last year their dad tried to force a custody change by keeping them. I filed for custody. He requested 50/50. The custody investigator suggested minimal time with dad due to his efforts of parental alienation and badmouthing me (this was from interviews with the children). Judge ruled for week on/week off between our homes. I live in a city 30 mins away from dad but work near there so the children were put in his school district. Went for a year like this, my son told me dad is smoking pot in front of them. He also yells at them for things beyond their control (especially the 12 year old) like child support, custody, etc. I filed for modification of custody. Judge denied a hearing but had the children see a custody investigator for one interview. The child that told me about the marijuana use did not disclose to the CI. After leaving the office he tells me this. I start recording and have on audio recording that dad told him "remember whatever you say that you are not only hurting me, you are hurting my whole family". Later that evening I hit record when both children started talking about dad yelling at my oldest before the interview. The younger one left and older one said (while still recording) that dad told him he didn't want him anymore, that all he has ever done is stab him in the back. I know I have the burden of proof but this is getting out of hand. Should I submit a new motion and include the audio recordings? Advice please?
<bot>: Son tells me dad smokes pot in front of the kids, judge denies a hearing to modify custody. Do I move forward with audio evidence?