Your W sounds a lot like mine. Tried to make me look bad, lied to the therapist about her OM. Lost all values with the kids and introduced them to things we worked years to prevent.
My kids are older and they wouldnt fall for her mania and lies. The therapist at the beginning was askng me what is wrong with me . Lol . I was all over the place, hurt, shell shocked, lost...then I took control of my emotions and in the end the therapist saw that STBXW was unstable and the kids were better with me. What I'm saying is , don't worry about how you think she is trying to make you look like the bad guy. Be the best dad you can be. Love your kids. Your W will make so many mistakes it will eventually catch up to her.
And believe me your kids willl grow to resent the OM. He's in it for himself.
As for your S. Watch over him. Your W is irrational about his diet. Continue what works for your son. Mine offered pot to my 14yr old at the time. STBXW was against pot and hated it prior to MLC. Now offered it lol . Their minds are in left field. You need to take the lead.
All the best Irish
M51 XW43 (38 at bd) BD1 MAY 30 2015 BD2 JUNE 25 2015 by text moved out Aug 2 2015 left both Daughters 13 and 15 (now 18-20) Her divorce Final July 26 2016 Last time she saw her kids Aug 2 2015