Welcome!
I'm so sorry for what you are going through but you are not alone. One of the hardest things to accept is that we have no control over what happens to our adult children. I and many others here know that helpless feeling.
Recoveringenabler has given you good advice about reaching out to NAMI.
If your son does have to serve time you can reach out to the facility he will be in and find out what kind of programs they have available. Find out as much as you can about the facility, what are theri visitation policy, how to put money on your son's account, what can you mail to him
Having a child in jail is something no parent ever wants to see happen. It can be scary but you do not have to let the fear consume you. My son has been in jail several times, currently serving 2 years. I don't like it but at least I know where he is opposed to him living on the streets.
I know you want to be there for your son but you must take good care of yourself first. I know as a mom that can sound strange because we always put our children and others first but if we as mothers do not take care of ourselves we will not be able to take care of others. Even if you can only carve out 15 minutes a day just for you, do it. Take some time to recharge, go for a walk, take a bubble bath, listen to some relaxing music, something that is just for you.
You are not alone. Please keep posting and let us know how things are going.
((HUGS)) for your hurting heart.