I wish I had more time to write a meaningful response. My sweet boy returned from his first year at school as a snarly, lying, slacking, pot using stranger. I spent an entire summer excusing his behavior as growing pains and burgeoning independence. I thought I could get him thru and back to school by lowering the bar. I was horrified by the very idea of him not returning to school in the fall. Long story short, 2 days before he was to return, his lying & pot use became too big to ignore. We refused to support him, asked him to stay home & get help & he rebelled & was estranged from us & out of school for 2 years.
That summer, I walked on eggshells for nothing. The worst case scenario became our lives. I found myself on this board the night he left. Gently & not so gently - the other posters pointed out that by placating him & excusing him, I handed him the power. It emboldened him. & I lost any chance I had to get thru to him.
So, I advise you to go for broke. Take a stand, draw a line in the sand. Work with you ex, find the common ground that is your love for your son & draw a line in the sand. Try to get thru to him, get him help if you can. And if you can't, realize that your reticence equals empowerment to your son. So, stand up for what's right.; don't lower the bar. It will get so low that it will crush you. Stand up for your own morals and know that by doing so- you are setting an example for your son. He won't realize it now, but he will someday.