Welcoming you,
Mom-Needs-Help 
Pretty well all of us here can truthfully say..."I know how you feel"...because we really, really do. To watch a loved-one (especially a child!) live such a troubled life plays havoc with our heart-strings. We could help them when they were small...so hard to help them now...so hard to save them from themselves.
Do you feel comfortable in sharing more about him and your relationship with him? How long has it been that he has been out-of-control? Has he ever had counselling? Has he ever had treatment?
You write that you believe he has BPD. That is echoed by many of us here, too, me included. While my daughter has been to many counsellors over the years, she has never been officially diagnosed as suffering from this mental illness but once I started to do my research into the types of behaviours she displays, the tick marks were there.
The thing is, Mom-Needs-Help, we are just as important as our children. While we do what we can to help them (when they give us the opportunity to do so!) we so need to look after ourselves. We need to stay confident in that we have done our best...will continue to do our best...BUT...we need our quality of life, too.
Do you have any support with family/friends? Have you ever sought out counselling for yourself? Have you given yourself periods of time where you can smell the roses...get genuine smiles on your face? By doing things like that you are not abandoning your child. You are role-modelling what life can/should be.
Believe me when I say you have come to an excellent spot for support...support as you start to learn of this sometimes very debilitating mental illness. Keep checking things out here. Keep reaching out with what is happening in this troubling relationship with your son. Do not ever think you are alone. Our stories here, although wide-ranging, strike cords with others.
Here's to sunnier days for you...and for all of us...as we plod along in these "different" times.
Here is a ((HUG)….from Huat
