Hi ACJ! I can see your utter frustration with all this --- who wouldn't be. Your H plays games, deserts the kids then they go to him, uses the kids against you (all so unfair), and you have tried so hard not to do the same. In a way, I am glad you told your son what's going on --- he's old enough. I reckon D14 goes back to H because that's the only way she has him, whereas, she knows you'll always be there for her.
Try not to worry too much about S16 --- he will find his way. Just love him, be interested in whatever he's doing (even if you don't agree) and let your early mothering do it's job. Nothing more you can do now but encourage and be his cheerleader. The same goes for the other children except D14 still needs boundaries.
Anyway, that's my 2c worth.
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim