In JW-Land nobody had the perfect parents even if they were not abusive some kids will find ways to attack their parents because it takes the responsiblity for any of their personal or financial failures and dump's it on their parental figures.
I had more than my fair share of listening to JW kids and parents turn a Shepherding Call into a Family Feud, some of these spiritual events are still gatherings I wish I never attended. When my sister went on the attack against my mother, she had a Top 100 List of how my parents "F'ed Up!" and let them have it! Kids get to a age where they begin to realize "life is short" and find ways to blame parents for their personal issues and do what the Society taught them to do, "kick parents when their feeling down and guilty" and chip away at any chink in your armor of humanity.
It's time to put your son in the "Penalty Box", the more you grovel and beg, the more he is going to walk on your like some old Afghan Rug. Unless you are really in the mood to be abused, take a time out because I can tell you from experience, the more you try to ask for forgiveness and understanding during their period of rage and bitterness you are the only one who is going to get more heart-broken. It's time to take a break and allow him and her time to cool off, even if it takes months or a year. Nothing good ever comes from chasing down people who are angry and do not wish to have a forum of open understanding or allow a third party to hear their grievances!