I was also wondering this. Is a family member diagnosed with BPD.
This particular board is for parents trying to support children with BPD and I wonder if you might get a better response on
[L5] Coping and Healing from a BPD Parent, Sibling, or Inlaw Board.
It is sad when relationships break down but sometimes people do feel that the only option is to distance themselves.
It would help to know more of your situation to direct you to the best help.
If he IS feeling low contact is necessary I think that it is good that he is trying to do it without a lot of drama.
Does he discuss his reasons with you?