Stress bunny, nothing is going to look that good for your son right now other than cleaning up his appearance (yes, it matters), and showing he is willing to join society. That probably means cleaning up and getting a job. My guess however is that he is addicted to something stronger than pot. I could be wrong, but his behaviors seem too reckless to blame pot for them. Right after he was busted for pot...he did it again??
Like you said, leniency was his, but he blew it. He either is taking something he can't stay away from and only got caught for the pot (but there is more) or he is totally irresponsible and is thumbing his nose at the court. That is never a good thing. If he is lucky, he WILL be able to choose drug rehab as an option, BUT if he is not ready to change his life around, he won't. It is impossible to make somebody stop using drugs just by putting them in a rehab.
Our system is tough. Maybe too tough. But it is what it is. I would make sure he has a good haircut (that I'd spring for) and clean clothes. And then you are throwing it all up to the judge who, in this situation, is God Himself. He makes the decision.
None of this had to happen. Your son didn't have to take drugs and drop out of society. He could have followed probably very simple house rules such as keeping his room clean, showering, working, maybe paying a little rent or maybe not, being respectful to the adults in the house and not doing anything illegal. Not hard for most eighteen year olds. Most do this. I have an eighteen year old myself.
If your husband is worried about his little girl, I get him. And if all of you are not on the same page regarding counseling, you can't make him go. I would not break up your daughter's family because of your son. Give yourself time...you can always decide to divorce him. Wait and see if things change for your son. He could get better or even worse and one day you too may not want him around your daughter. At any rate, it's really a pity that he won't go to counseling, but you can't make him go any more than you can make your son clean and sober and eager to obey the law.
Work on yourself, the one person whom you have 100% control over. I highly recommend a few books to read. Since you are a Christian, I really have to recommend "Boundaries" by Townsend and Cloud. You will read, from a Christian perspective, how to treat the others in your life who try to control you, including your spouse and your son and I believe it will really resonate with you. You actually don't have to be a Christian to gain from it's wisdom, but since you are it will probably give you even MORE help. Then I think you ought to read "Codependent No More" by Melodie Beattie (I may have spelled her name wrong). That was the first book I read that actually gave me permission not to take care of the entire world...and made me believe it. Others had told me that, including therapists, but only she put in such a way that I was able to put myself first sometimes and not feel like a selfish b****h
You sound like a wonderful, caring woman who has had many bad cards thrown in your direction. It is time those cards start blowing the other way and you start being as good to yourself as you have tried to be to others. None of the things you look back at and feel guilty about were done maliciously. None of them were done to harm anyone. Your son, in his heart, knows how much you love him and that you did not mean to make the mistakes you made and that all of us make...trust me you are NOT alone.
Because you and your husband share a precious daughter, I hope you two can find a way to come together regarding your son. I can see his point of view and yours. And I remember how my babies used to cry and cover their ears when my daughter was high and angry in the house.
Try to have a serene night. Nothing needs to be solved today, this minute. See how things go. None of us can predict the future. Ultimately, your son's future is in his hands.
Hugs for your hurting mommy heart.