What to do about my oldest son ?

  I don't know what or how to help him.  So many problems of my own and I just don't need this, even tho it breaks my heart, there's nothing I can do.  He has to be the one who changes things.  This is why my husband wished he could "leave his boys in a good place".  He knew that at least one of them is hardcore alcoholic.  He wanted to try to help them.  I know they have to want to help their own self.
  Last night, at 1;30A.M. , my oldest sons' girlfriend called me to see if he was at my house or if I had seen him.  She showed me a text he had wrote her sounding a little suicidal. We walked my yards, front and back with flashlights, wading the dew.  He finally came home to his house abt. 3:00 a.m.  He had been out walking somewhere, we don't know where.  I feel like I have had so much to deal with and now this ?  I am having tests done on my heart because of my high blood pressure, am being weaned-off my high doseage of pain medication and my body is feeling it.  Life just seems to be dumping on me lately and I wonder,"WTH is going on ?  I want to help my son but sense he didn't go into rehab and said he can do this on his own, I hope he can but I think it could be dangerous for him, the DT's withdrawl.  I can not sit with him, his girlfriend and his former mother-in-law are going to be taking care of him.  I will come over if they or he calls me.  Other than that I know that I need to take care of me too.  I feel selfish and hardhearted but then I would help him anyway I could but I can not watch him in pain. I have seen too much of that for 5 years. But I will give money for rehab if he would only go.  I'm sad, very sad, no mother wants this for her child, not ever !!!