Hi Radioguitarguy
My 28yr daughter is also fighting to be well, in treatment. I can relate to your journey and your sons, it’s certainly not easy, it is however a great stride forward to be congratulated.
We arrived at the same point you have ‘Three things have to happen before the healing can happen:
1. Accepting the BPD diagnosis... .
2. Knowing one must 'do the work' by finding a good therapist and possibly medication... .
3. Actually 'doing the work' on a consistent basis... .’
Yes it would be good to ‘sit down and actually find out what he thinks', establishing common ground and an agreed plan has helped us.
1) My 28yr daughter has set personal goals at DBT and more recently is working towards establishing her personal values.
2) DD became freelance this April at her employers suggestion - having entered crisis early last year and struggling to deliver work, this has taken the immediate pressure off her now, for her to take the lead and responsibility of what she feels able to deliver and work the hours she feels able, small steps. Her income has reduced and for now that is ok as she invests her time to recover - goal number one. DD lives at home and pays rent, she covers all her travel and her personal wellbeing costs, contact lenses, dental costs... .my budget and her budget are on the kitchen wall, clear In light of her focusing her efforts on her recovery and at this point working less her rent has accordingly been reduced.
Our present agreement in priority:
1) To be well, attend DBT, work towards recovery is DD's no 1 priority.
2) Be mindful and flexible of current employment that works to support her investment in recovery.
3) Attend housing co-op meetings in hope of housing at a reasonable sustainable rent, that is likely to many years before being housed.

4) During or after recovery engage a personal life coach to help DD work through her future career plans so she can sustain living independently in the future.
Realistically there is easily a further three-five years of work in progress for DD to be well, able and confident to safely manage her future independently. From time to time we explore 'able' and 'enabled'.
I believe your son may welcome an open conversation about his future independence -my daughter has appreciated, it’s taken the pressure off and is always discussed in the context of our agreed No 1 priority for her to invest in treatment and recovery, that’s her focus for now, which I respect. Everything comes after and yes it’s good to talk and prepare for the future.
WDx