Echo, I think all of us have helped our kids out a little, although they don't really learn from it or appreciate it and, if the deliberately bad behavior continues, many also cut their kids off cold. When my daughter was drug using she got into a serious car accident that was her fault and she was sued for $14,000. We had stopped putting her on our insurance and it wasn't even our car she was driving plus she was over 18 so it became her debt. Long after she stopped using drugs she still owed the money so her father reluctantly paid most of it. BUT...remember, she had already made a decision to cut ties from her drugged lifestyle and was by then doing very well.This is always hard.
Because you have to life with your decisions, maybe pay this but make it clear to him that it is the last $$$ you pay to get him out of trouble and then, if it were me, I'd stick to it. My daughter was using anything she could inhale or snort and even inject until we stopped giving her a cushy place to sleep, the certainty (in her mind) that we would never really put her out of the house, and lots of love and nurturing. In response, she stole from us, lied to us constantly, and put herself at extreme risk. I thought she'd end up in jail or die. She was doing meth and weighed maybe 80 lbs. and looked like death warmed over and refused any treatment.
We did make her leave, but she got her brother to take her in. However, and I think I already talked about her time with him, he is a very rigid, self-righteous person and told her that if she lit up one cigarette and he found out about it, he'd toss her out in the cold and not feel bad about it. And she knew he meant it. She hated living there, but she got clean. And, during that time, she had to walk back and forth to work (at Subway) and that was the only money she had. Nobody helped her. She quit. Did she quit because her "soft place to land" had been pulled out from under her? She says it was both a personal decision because she was sick of herself and also because she did not to end up homeless and alone. When we first made her leave, she was FURIOUS with me and told me she'd never speak to me again, but as she got clean and time went on, it didn't last and we are very close today and she is a great, GREAT young adult.
Helping drug users doesn't work. Jail can sometimes keep them off the street, give them free meals and a place to sleep. What is better? Jail or out on the street or in our homes causing mayhem for us and our other loved ones? I personally would not allow this adult child back into my home, but that is another personal decision you have to make. But it will not help him to allow him back. It may make YOU feel less guilty, but it won't make HIM any better unless he is asking, very seriously, for help to change.
I would not help him contact the girlfriend. She is not his friend. She is just one of his "friends" (as I called the people my daughter hung with) who is helping him accept that drug use is ok. Better for him if she is gone. One less druggie in his circle.
Hugs to you. As I type, I remember and the feelings come back and it is just so hard. After Daughter left to live with Son, which I knew would be very unpleasant for her, I cried for three weeks wondering if I'd done the right thing, remembering her words of hate toward me. But according to my daughter, it saved her life and made her seriously think about what she was doing and it took her away from her pushy drug using peers, who wouldn't leave her alone even when she WANTED to quit. She would get threats and roughing up from them...drug life is not pleasant. Apparently she owed some druggie money and didn't have it and he was threatening her life. I'm not sure jail is more dangerous than using drugs..your child is still hanging out with dangerous people and there is no protection on the street. My daughter left the state when she went to live with her brother, and that was a huge help. The dangerous peers didn't know where she was and she had a chance to start over.