When Do Children Really Grow Up ?

I am 52 years old. I have not always made the right decisions but I have tried to make the best of what the out come was. It seems to me that the children of the 70`s are not growing up that is to say that at the age my kids are now I was set in my life and the way I was going. It may not have been what was best but it was the way I saw it. My kids are now 34,33, 30. They have had a hard time growing up as I went through a nasty divorce  at the age of 32 myself and was left to care for my kids alone. You see back then the dead beat fathers did not have any recourse for not paying their child support. I know that it was hard on us all. There were times we had no water,electric, or phone and sometimes not much to eat. I also had to be gone a lot I worked two jobs to try to survive. My oldest helped my by sitting with her brothers while I was away.She had lots of responsibility and has since always been the one with her head on straight for the most part. She takes care of herself with little help from anyone. I can not say the same for the two younger boys. They have taken the longest to get themselves together or should I say one of them has. The youngest has finally got a great job and a nice family and puts things in the right order as far as job, family and life goes. He was a mess for a long time. He went through the drinking and drug age for about 7 years. As a result he has made life hard on himself.  He was in dept because of all the things he did wrong like tickets, credit cards and just wasting money on drugs and beer. Thank God he has changed the way he was going. Now as for the middle boy he has always been the one who did not care who he hurt or if what he was doing was bad or illegal.
We have recently found out that he is bi-polar which does account for a lot of or maybe all of the stuff he has done or is still doing. I have read all I can find out about it but this is not helping. When he was in his 20`s he did okay for him and his family, he still did crazy stuff but his wife held him together for the most part. She did put up with a lot. She and he got a divorce last year two weeks after their second son was born. He also had a son with an other woman while he and his wife were separated and his wife took on the role of helping him with that child too because they were back together. Now that they have split he is so out of control. He has no real job and no insurance either so he can not get meds for his disease and things are just getting worse. He has been living with a younger girl for a while but they have a rocky relationship and now she is going to have a baby too! What is it that I can do ? He is unable to comprehend what is right and wrong it seems. He is angry all the time and flies off the handle at the drop of a hat, so when I try to talk some since into him he just gets mad. I am at my wits end here, I do not even want to see him or hear from him because I don`t know what bad news is next. Everyone of us has given him money at one time or another and we never get paid back so we are all tired of this. I still think he believes he has nothing wrong with himself. Part of the disease is that you don`t think anything medical is wrong even though he has seen a few doctors. He has very high highs and very low lows. He does not see it though. How long am I going to be able to cope with this ? I feel like he is still 15 and I can not control him. This is more pain than I ever thought I would have to stand. I feel like it is never going to end until I die and I don`t want all this pain anymore. I never thought I would make it this far and still have all this pain in my heart. He is and has put the whole family and then some through hell and he does not see it at all. When will it be my time to say I have done a good job and let go of all the worry or is it right to stop being the leaning post for his problems. I have not told you near the stuff he has done but I don`t think I have the time left on this earth to tell you all that entails. I am just hoping that writing this may help me feel better in some way. Maybe someone out there has an answer or maybe if they are having the same kind of problem they will know they are not alone.